Restore `JoinablePath.[is_]relative_to()`, which were deleted in
ef63cca494. These methods are too useful to
forgo. Restore old tests, and add new tests covering path classes with
non-overridden `__eq__()` and `__hash__()`.
Slightly simplify `PurePath.relative_to()` while we're in the area.
No change to public APIs, because the pathlib ABCs are still private.
Adjust the tests for the `pathlib.types` module so that they can be run
against the `pathlib-abc` PyPI package, which is a backport of the module
for older Python versions.
Specifically, we add a `.support.is_pypi` switch that is false in the
stdlib and true in the pathlib-abc package. This controls which package
we import, and whether or not we run tests against `PurePath` and `Path`.
For compatibility with older Python versions, we stop using
`zipfile.ZipFile.mkdir()` and `zipfile.ZipInfo._for_archive()`.
Remove the *case_sensitive* argument from `_JoinablePath.full_match()` and
`_ReadablePath.glob()`. Using a non-native case sensitivity forces the use
of "case-pedantic" globbing, where we `iterdir()` even for non-wildcard
pattern segments. But it's hard to know when to enable this mode, as
case-sensitivity can vary by directory, so `_PathParser.normcase()` doesn't
always give the full picture. The `Path.glob()` implementation is forced to
make an educated guess, but we can avoid the issue in the ABCs by dropping
the *case_sensitive* argument.
(I probably shouldn't have added these arguments in `PurePath` and `Path`
in the first place!)
Also drop support for `_ReadablePath.glob(recurse_symlinks=False)`, which
makes recursive globbing much slower.
Test `pathlib.types._JoinablePath` in a dedicated test module. These tests
cover `LexicalPath`, `PurePath` and `Path`, where `LexicalPath` is defined
in a new `test.test_pathlib.support` package.
