The new test fails on x86 and arm64 public macOS bots:
```
09:27:59  ======================================================================
09:27:59  FAIL: test_append_frames (TestScriptedFrameProvider.ScriptedFrameProviderTestCase)
09:27:59     Test that we can add frames after real stack.
09:27:59  ----------------------------------------------------------------------
09:27:59  Traceback (most recent call last):
09:27:59    File "/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/llvm-project/lldb/test/API/functionalities/scripted_frame_provider/TestScriptedFrameProvider.py", line 122, in test_append_frames
09:27:59      self.assertEqual(new_frame_count, original_frame_count + 1)
09:27:59  AssertionError: 5 != 6
09:27:59  Config=arm64-/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/lldb-build/bin/clang
09:27:59  ======================================================================
09:27:59  FAIL: test_applies_to_thread (TestScriptedFrameProvider.ScriptedFrameProviderTestCase)
09:27:59     Test that applies_to_thread filters which threads get the provider.
09:27:59  ----------------------------------------------------------------------
09:27:59  Traceback (most recent call last):
09:27:59    File "/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/llvm-project/lldb/test/API/functionalities/scripted_frame_provider/TestScriptedFrameProvider.py", line 218, in test_applies_to_thread
09:27:59      self.assertEqual(
09:27:59  AssertionError: 5 != 1 : Thread with ID 1 should have 1 synthetic frame
09:27:59  Config=arm64-/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/lldb-build/bin/clang
09:27:59  ======================================================================
09:27:59  FAIL: test_prepend_frames (TestScriptedFrameProvider.ScriptedFrameProviderTestCase)
09:27:59     Test that we can add frames before real stack.
09:27:59  ----------------------------------------------------------------------
09:27:59  Traceback (most recent call last):
09:27:59    File "/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/llvm-project/lldb/test/API/functionalities/scripted_frame_provider/TestScriptedFrameProvider.py", line 84, in test_prepend_frames
09:27:59      self.assertEqual(new_frame_count, original_frame_count + 2)
09:27:59  AssertionError: 5 != 7
09:27:59  Config=arm64-/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/lldb-build/bin/clang
09:27:59  ======================================================================
09:27:59  FAIL: test_remove_frame_provider_by_id (TestScriptedFrameProvider.ScriptedFrameProviderTestCase)
09:27:59     Test that RemoveScriptedFrameProvider removes a specific provider by ID.
09:27:59  ----------------------------------------------------------------------
09:27:59  Traceback (most recent call last):
09:27:59    File "/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/llvm-project/lldb/test/API/functionalities/scripted_frame_provider/TestScriptedFrameProvider.py", line 272, in test_remove_frame_provider_by_id
09:27:59      self.assertEqual(thread.GetNumFrames(), 3, "Should have 3 synthetic frames")
09:27:59  AssertionError: 5 != 3 : Should have 3 synthetic frames
09:27:59  Config=arm64-/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/lldb-build/bin/clang
09:27:59  ======================================================================
09:27:59  FAIL: test_replace_all_frames (TestScriptedFrameProvider.ScriptedFrameProviderTestCase)
09:27:59     Test that we can replace the entire stack.
09:27:59  ----------------------------------------------------------------------
09:27:59  Traceback (most recent call last):
09:27:59    File "/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/llvm-project/lldb/test/API/functionalities/scripted_frame_provider/TestScriptedFrameProvider.py", line 41, in test_replace_all_frames
09:27:59      self.assertEqual(thread.GetNumFrames(), 3, "Should have 3 synthetic frames")
09:27:59  AssertionError: 5 != 3 : Should have 3 synthetic frames
09:27:59  Config=arm64-/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/lldb-build/bin/clang
09:27:59  ======================================================================
09:27:59  FAIL: test_scripted_frame_objects (TestScriptedFrameProvider.ScriptedFrameProviderTestCase)
09:27:59     Test that provider can return ScriptedFrame objects.
09:27:59  ----------------------------------------------------------------------
09:27:59  Traceback (most recent call last):
09:27:59    File "/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/llvm-project/lldb/test/API/functionalities/scripted_frame_provider/TestScriptedFrameProvider.py", line 159, in test_scripted_frame_objects
09:27:59      self.assertEqual(frame0.GetFunctionName(), "custom_scripted_frame_0")
09:27:59  AssertionError: 'thread_func(int)' != 'custom_scripted_frame_0'
09:27:59  - thread_func(int)
09:27:59  + custom_scripted_frame_0
09:27:59  
09:27:59  Config=arm64-/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/lldb-build/bin/clang
09:27:59  ----------------------------------------------------------------------
09:27:59  Ran 6 tests in 14.242s
09:27:59  
09:27:59  FAILED (failures=6)
```

Reverts llvm/llvm-project#161870

This patch extends ScriptedFrame to work with real (non-scripted)
threads,
enabling frame providers to synthesize frames for native processes.

Previously, ScriptedFrame only worked within
ScriptedProcess/ScriptedThread
contexts. This patch decouples ScriptedFrame from ScriptedThread,
allowing
users to augment or replace stack frames in real debugging sessions for
use
cases like custom calling conventions, reconstructing corrupted frames
from
core files, or adding diagnostic frames.

Key changes:

- ScriptedFrame::Create() now accepts ThreadSP instead of requiring
ScriptedThread, extracting architecture from the target triple rather
than ScriptedProcess.arch

- Added SBTarget::RegisterScriptedFrameProvider() and
ClearScriptedFrameProvider() APIs, with Target storing a
SyntheticFrameProviderDescriptor template for new threads

- Added "target frame-provider register/clear" commands for CLI access

- Thread class gains LoadScriptedFrameProvider(),
ClearScriptedFrameProvider(),
and GetFrameProvider() methods for per-thread frame provider management

- New SyntheticStackFrameList overrides FetchFramesUpTo() to lazily
provide
frames from either the frame provider or the real stack

This enables practical use of the SyntheticFrameProvider infrastructure
in
real debugging workflows.

rdar://161834688

Signed-off-by: Med Ismail Bennani <ismail@bennani.ma>

Signed-off-by: Med Ismail Bennani <ismail@bennani.ma>

We're iterating over the stop hooks so if one of them changes the stop
hook list by deleting itself or another stop hook, that invalidates our
iterator.

I chose to fix this by making a copy of the stop hook list and iterating
over that. That's a cheap operation since this is just an array of
shared pointers. But more importantly doing it this way means that if on
a stop where one stop hook deletes another, the deleted hook will always
get a chance to run. If you iterated over the list itself, then whether
that to be deleted hook gets to run would be dependent on whether it was
before or after the deleting stop hook, which would be confusing.

Introduce the concept of internal stop hooks.
These are similar to LLDB's internal breakpoints:
LLDB itself will add them and users of LLDB will
not be able to add or remove them.

This change adds the following 3
independently-useful concepts:
* Maintain a list of internal stop hooks that will be populated by LLDB
and cannot be added to or removed from by users. They are managed in a
separate list in `Target::m_internal_stop_hooks`.
* `StopHookKind:CodeBased` and `StopHookCoded` represent a stop hook
defined by a C++ code callback (instead of command line expressions or a
Python class).
* Stop hooks that do not print any output can now also suppress the
printing of their header and description when they are hit via
`StopHook::GetSuppressOutput`.

Combining these 3 concepts we can model "internal
stop hooks" which serve the same function as
LLDB's internal breakpoints: executing built-in,
LLDB-defined behavior, leveraging the existing
mechanism of stop hooks.

This change also simplifies
`Target::RunStopHooks`.  We already have to
materialize a new list for combining internal and
user stop hooks. Filter and only add active hooks to this list to avoid
the need for "isActive?"
checks later on.

Fixes some casing mistakes I added in #161581

This patch adds a load core time, right now we don't have much insight
into the performance of load core, especially for large coredumps. To
start collecting information on this I've added some minor
instrumentation code to measure the two call sites of `LoadCore`.

I've also added a test to validate the new metric is output in
statistics dump

This PR is a part of the effort to make the VFS used in the compiler
more explicit and consistent.

Instead of creating the VFS deep within the compiler (in
`CompilerInstance::createFileManager()`), clients are now required to
explicitly call `CompilerInstance::createVirtualFileSystem()` and
provide the base VFS from the outside.

This PR also helps in breaking up the dependency cycle where creating a
properly configured `DiagnosticsEngine` requires a properly configured
VFS, but creating properly configuring a VFS requires the
`DiagnosticsEngine`.

Both `CompilerInstance::create{FileManager,Diagnostics}()` now just use
the VFS already in `CompilerInstance` instead of taking one as a
parameter, making the VFS consistent across the instance sub-object.

This patch causes the various AST dump commands (`target modules dump
ast`/`target dump typesystem`) to be color-highlighted. I added a `bool
show_color` parameter to `SymbolFile::DumpClangAST` and
`TypeSystem::Dump`. In `TypeSystemClang` I temporarily sets the
`getShowColors` flag on the owned Clang AST (using an RAII helper) for
the duration of the AST dump. We use `Debugger::GetUseColors` to decide
whether to color the AST dump.

The LLVM Style Guide says the following about error and warning messages
[1]:

> [T]o match error message styles commonly produced by other tools,
> start the first sentence with a lowercase letter, and finish the last
> sentence without a period, if it would end in one otherwise.

I often provide this feedback during code review, but we still have a
bunch of places where we have inconsistent error message, which bothers
me as a user. This PR identifies a handful of those places and updates
the messages to be consistent.

[1] https://llvm.org/docs/CodingStandards.html#error-and-warning-messages

Whenever an option would use something other than the first letter of
the long option as the short option, Jim would capitalized the letter we
picked as a mnemonic. This has often been mistaken for a typo and Jim
wondered if we should stop doing this.

During the discussion, David mentioned how this reminds him of the
underline in menu bars when holding down alt. I suggested we do
something similar in LLDB by underlying the letter in the description.

https://discourse.llvm.org/t/should-we-remove-the-capital-letter-in-option-helps/87816