The frame recognizer for the instrumentation runtimes (added in
https://github.com/llvm/llvm-project/pull/133079) only triggers on Darwin
for `libclang_rt`. Adjust the tests accordingly.

Since https://github.com/llvm/llvm-project/pull/133079 we no longer stop
in the stanitizer library when hitting a sanitizer breakpoint. Adjust
the test accordingly.

This uses [teyit](https://pypi.org/project/teyit/) to modernize asserts,
as recommended by the [unittest release
notes](https://docs.python.org/3.12/whatsnew/3.12.html#id3).

For example, `assertTrue(a == b)` is replaced with `assertEqual(a, b)`.
This produces better error messages, e.g. `error: unexpectedly found 1
and 2 to be different` instead of `error: False`.

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

This reverts commit 92a8dc0735cfb3f296f0c487b20d8fa8474e3e40 because
66d4ce7e26a5ab00f7e4946b6e1bac8f805010fa was reverted in 09859113ed23.

See ongoing discussion in https://reviews.llvm.org/D112603.

Speed up testing by not rerunning the test for all debug info variants.

The test flaked on bots:
http://green.lab.llvm.org/green/job/lldb-cmake/38666/
The test expects that tsan will detect a single race
with concurrent memory accesses. TSan doesn't do this reliably.
Run 100 iterations of the racing threads, which should
make the race much more likely to be detected.

Reviewed By: melver

Differential Revision: https://reviews.llvm.org/D114444

For improved failure messages, use `assertIn` over `assertTrue`.

Differential Revision: https://reviews.llvm.org/D96095