This PR adds type summaries for
`std::{string,wstring,u8string,u16string,u32string}` from the MSVC STL.

See https://github.com/llvm/llvm-project/issues/24834 for the MSVC STL
issue.

The following changes were made:

- `dotest.py` now detects if the MSVC STL is available. It does so by
looking at the target triple, which is an additional argument passed
from Lit. It specifically checks for `windows-msvc` to not match on
`windows-gnu` (i.e. MinGW/Cygwin).
- (The main part): Added support for summarizing `std::(w)string` from
MSVC's STL. Because the type names from the libstdc++ (pre C++ 11)
string types are the same as on MSVC's STL, `CXXCompositeSummaryFormat`
is used with two entries, one for MSVC's STL and one for libstdc++.
With MSVC's STL, `std::u{8,16,32}string` is also handled. These aren't
handled for libstdc++, so I put them in `LoadMsvcStlFormatters`.

This is an ongoing series of commits that are reformatting our Python
code. Reformatting is done with `black` (23.1.0).

If you end up having problems merging this commit because you have made
changes to a python file, the best way to handle that is to run `git
checkout --ours <yourfile>` and then reformat it with black.

RFC: https://discourse.llvm.org/t/rfc-document-and-standardize-python-code-style

Differential revision: https://reviews.llvm.org/D151460

Embedded nul characters are still printed, and they don't terminate the
string. See also D111634.

Differential Revision: https://reviews.llvm.org/D120803

It conflicts with the summary for BOOL * (aka signed char *). This
partially reverts D112709.

They were being applied too narrowly (they didn't cover signed char *,
for instance), and too broadly (they covered SomeTemplate<char[6]>) at
the same time.

Differential Revision: https://reviews.llvm.org/D112709

When we know the bounds of the array, print any embedded nuls instead of
treating them as terminators. An exception to this rule is made for the
nul character at the very end of the string. We don't print that, as
otherwise 99% of the strings would end in \0. This way the strings
usually come out the same as how the user typed it into the compiler
(char foo[] = "with\0nuls"). It also matches how they come out in gdb.

This resolves a FIXME left from D111399, and leaves another FIXME for dealing
with nul characters in "escape-non-printables=false" mode. In this mode the
characters cause the entire summary string to be terminated prematurely.

Differential Revision: https://reviews.llvm.org/D111634

I believe this is a more natural behavior, and it also matches what gdb
does.

Differential Revision: https://reviews.llvm.org/D111399

Summary:
Around a third of our test sources have LLVM license headers. This patch removes those headers from all test
sources and also fixes any tests that depended on the length of the license header.

The reasons for this are:

* A few tests verify line numbers and will start failing if the number of lines in the LLVM license header changes. Once I landed my patch for valid SourceLocations in debug info we will probably have even more tests that verify line numbers.
* No other LLVM project is putting license headers in its test files to my knowledge.
* They make the test sources much more verbose than they have to be. Several tests have longer license headers than the actual test source.

For the record, the following tests had their line numbers changed to pass with the removal of the license header:
    lldb-api :: functionalities/breakpoint/breakpoint_by_line_and_column/TestBreakpointByLineAndColumn.py
    lldb-shell :: Reproducer/TestGDBRemoteRepro.test
    lldb-shell :: Reproducer/TestMultipleTargets.test
    lldb-shell :: Reproducer/TestReuseDirectory.test
    lldb-shell :: ExecControl/StopHook/stop-hook-threads.test
    lldb-shell :: ExecControl/StopHook/stop-hook.test
    lldb-api :: lang/objc/exceptions/TestObjCExceptions.py

Reviewers: #lldb, espindola, JDevlieghere

Reviewed By: #lldb, JDevlieghere

Subscribers: emaste, aprantl, arphaman, JDevlieghere, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D74839

Summary: Moves lldbsuite tests to lldb/test/API.

This is a largely mechanical change, moved with the following steps:

```
rm lldb/test/API/testcases
mkdir -p lldb/test/API/{test_runner/test,tools/lldb-{server,vscode}}
mv lldb/packages/Python/lldbsuite/test/test_runner/test lldb/test/API/test_runner
for d in $(find lldb/packages/Python/lldbsuite/test/* -maxdepth 0 -type d | egrep -v "make|plugins|test_runner|tools"); do mv $d lldb/test/API; done
for d in $(find lldb/packages/Python/lldbsuite/test/tools/lldb-vscode -maxdepth 1 -mindepth 1 | grep -v ".py"); do mv $d lldb/test/API/tools/lldb-vscode; done
for d in $(find lldb/packages/Python/lldbsuite/test/tools/lldb-server -maxdepth 1 -mindepth 1 | egrep -v "gdbremote_testcase.py|lldbgdbserverutils.py|socket_packet_pump.py"); do mv $d lldb/test/API/tools/lldb-server; done
```

lldb/packages/Python/lldbsuite/__init__.py and lldb/test/API/lit.cfg.py were also updated with the new directory structure.

Reviewers: labath, JDevlieghere

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D71151