When a test depends on a new debugserver feature/fix, the API test must
be marked @skipIfOutOfTreeDebugserver because the macOS CI bots test
using the latest Xcode release debugserver. But over time all of these
fixes & new features are picked up in the Xcode debugserver and these
skips can be removed.

We may see unexpected test failures from removing all of these 1+ year
old skips, but that's likely a separate reason the test is failing that
is being papered over by this skip.

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

Skip another batch of tests that don't really make sense to run
remotely.

These two tests, TestSkinnyCorefile.py and TestStackCorefile.py,
require a new debugserver on darwin systems to run correctly; for now,
skip them if the system debugserver is in use.  There's no easy way to
test if the debugserver being used supports either of these memory
region info features. For end users, the fallback will be a full
corefile and that's not the worst thing, but for the tests it is a
problem.

Add a field to the qMemoryRegionInfo packet where the remote stub
can describe the type of memory -- heap, stack.  Keep track of
memory regions that are stack memory in lldb.  Add a new "--style
stack" to process save-core to request that only stack memory be
included in the corefile.

Differential Revision: https://reviews.llvm.org/D107625