This is NFC, I'm modernizing the interface before I add to it in a
subsequent commit.

Target::ReadMemory may or may not read live memory, but whether it did
read from live memory or from the filecache is opaque to callers. Add an
extra out parameter to indicate whether live memory was read or not.

c72c0b298c13 fixed a race condition in Target::GetExecutableModule. The
patch originally added the lock_guard but I suggested using the locking
ModuleList::Modules() helper instead. That didn't consider that the
fallback would still access the ModuleList without holding the lock.
This patch fixes the remaining issue.

…ess" (#144810)

This relands commit e0933ab5ae4856c4aa188a5ea16716b3a8d0840b. The
original commit was causing the test TestCreateAfterAttach.py to fail on
ARM Ubuntu bots. It's possible that this could've been happening because
the test for wait-attach progress reporting is waiting on a process
named "a.out" which could be too generic as multiple other tests (when
run in parallel on the bots) could also be using processes named
"a.out". This commit changes the wait-attach progress report test to
wait on a unique process name.

Original PR description:

This commit adds a progress report when wait-attaching to a process as
well as a test for this.

Original PR link: https://github.com/llvm/llvm-project/pull/144768

This is breaking TestCreateAfterAttach.py on Ubuntu:

```
======================================================================
FAIL: test_create_after_attach_dwo (TestCreateAfterAttach.CreateAfterAttachTestCase.test_create_after_attach_dwo)
   Test thread creation after process attach.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/llvm-project/lldb/packages/Python/lldbsuite/test/lldbtest.py", line 1804, in test_method
    return attrvalue(self)
           ^^^^^^^^^^^^^^^
  File "/home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/llvm-project/lldb/packages/Python/lldbsuite/test/decorators.py", line 149, in wrapper
    return func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^
  File "/home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/llvm-project/lldb/test/API/functionalities/thread/create_after_attach/TestCreateAfterAttach.py", line 36, in test_create_after_attach
    self.runCmd("process attach -p " + str(pid))
  File "/home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/llvm-project/lldb/packages/Python/lldbsuite/test/lldbtest.py", line 1005, in runCmd
    self.assertTrue(self.res.Succeeded(), msg + output)
AssertionError: False is not true : Command 'process attach -p 1474309' did not return successfully
Error output:
error: attach failed: lost connection
```

on the buildbots for lldb-remote-linux-ubuntu, lldb-arm-ubuntu,
lldb-aarch64-ubuntu, lldb-arm-ubuntu.

This commit adds a progress report when wait-attaching to a process as
well as a test for this.

Since this PR: https://github.com/llvm/llvm-project/pull/141670/ We
started to override the Platform/Arch for a target if needed. However we
may have already registered locate module callback with the old
platform.

This PR will move the locate module callback to the new Platform
whenever Target changes architecture.

Co-authored-by: George Hu <georgehuyubo@gmail.com>

Use the locking iterator to ensure module don't change during iteration.

We're reading from the object's vtable to determine the pointer to the
full object. The vtable is normally in the "rodata" section of the
executable, which is often not included in the core file because it's
not supposed to change and the debugger can extrapolate its contents
from the executable file. We weren't doing that.

This patch changes the read operation to use the target class (which
falls back onto the executable module as expected) and adds the missing
ReadSignedIntegerFromMemory API. The fix is tested by creating a core
(minidump) file which deliberately omits the vtable pointer.