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`.

assertEquals is a deprecated alias for assertEqual and has been removed
in Python 3.12. This wasn't an issue previously because we used a
vendored version of the unittest module. Now that we use the built-in
version this gets updated together with the Python version used to run
the test suite.

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

Eliminate boilerplate of having each test manually assign to `mydir` by calling
`compute_mydir` in lldbtest.py.

Differential Revision: https://reviews.llvm.org/D128077

There is a .categories file in the python_api directory that makes all nested tests
belong to the category "pyapi". The decorator is unnecessary for these tests.

Follow up to D95813, this converts multiline assertTrue to assertEqual.

Differential Revision: https://reviews.llvm.org/D95899

Summary:
The error message from the construct `assertTrue(a == b, "msg") ` are nearly always completely useless for actually debugging the issue.
This patch is just replacing this construct (and similar ones like `assertTrue(a != b, ...)` with the proper call to assertEqual or assertNotEquals.

This patch was mostly written by a shell script with some manual verification afterwards:
```
lang=python
import sys

def sanitize_line(line):
  if line.strip().startswith("self.assertTrue(") and " == " in line:
    line = line.replace("self.assertTrue(", "self.assertEquals(")
    line = line.replace(" == ", ", ", 1)
  if line.strip().startswith("self.assertTrue(") and " != " in line:
    line = line.replace("self.assertTrue(", "self.assertNotEqual(")
    line = line.replace(" != ", ", ", 1)
  return line

for a in sys.argv[1:]:
  with open(a, "r") as f:
    lines = f.readlines()
  with open(a, "w") as f:
    for line in lines:
      f.write(sanitize_line(line))
```

Reviewers: labath, JDevlieghere

Reviewed By: labath

Subscribers: abidh, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D74475

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