test_walk_above_recursion_limit uses absolute limits

[mhsmith]

Bug report

Bug description:

os.walk and Path.walk both have a test verifying that they're not implemented recursively. However, their recursion limits are absolute rather than relative to the current frame. Since the test framework itself already consumes about 30 frames, it only takes a few extra frames to cause a spurious failure. This can easily happen when running the tests within another script, which happens in the Android testbed.

For example, if the limit in test_pathlib is reduced from 40 to 35:

======================================================================
ERROR: test_walk_above_recursion_limit (test.test_pathlib.test_pathlib.PosixPathTest.test_walk_above_recursion_limit)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/msmith/git/python/cpython/Lib/pathlib/__init__.py", line 241, in __str__
    return self._str
           ^^^^^^^^^
AttributeError: 'PosixPath' object has no attribute '_str'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/msmith/git/python/cpython/Lib/pathlib/__init__.py", line 300, in drive
    return self._drv
           ^^^^^^^^^
AttributeError: 'PosixPath' object has no attribute '_drv'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/msmith/git/python/cpython/Lib/test/test_pathlib/test_pathlib.py", line 1203, in test_walk_above_recursion_limit
    list(base.walk())
    ~~~~^^^^^^^^^^^^^
  File "/Users/msmith/git/python/cpython/Lib/pathlib/_abc.py", line 875, in walk
    scandir_obj = path._scandir()
                  ~~~~~~~~~~~~~^^
  File "/Users/msmith/git/python/cpython/Lib/pathlib/__init__.py", line 588, in _scandir
    return os.scandir(self)
           ~~~~~~~~~~^^^^^^
  File "/Users/msmith/git/python/cpython/Lib/pathlib/__init__.py", line 177, in __fspath__
    return str(self)
           ~~~^^^^^^
  File "/Users/msmith/git/python/cpython/Lib/pathlib/__init__.py", line 243, in __str__
    self._str = self._format_parsed_parts(self.drive, self.root,
                                          ^^^^^^^^^^
  File "/Users/msmith/git/python/cpython/Lib/pathlib/__init__.py", line 302, in drive
    self._drv, self._root, self._tail_cached = self._parse_path(self._raw_path)
                                                                ^^^^^^^^^^^^^^
  File "/Users/msmith/git/python/cpython/Lib/pathlib/__init__.py", line 293, in _raw_path
    path = self.pathmod.join(*paths)
           ~~~~~~~~~~~~~~~~~^^^^^^^^
  File "<frozen posixpath>", line 77, in join
RecursionError: maximum recursion depth exceeded

CPython versions tested on:

CPython main branch

Operating systems tested on:

• macOS
• Android

Linked PRs

• gh-116057: Use relative recursion limits when testing os.walk and Path.walk #116058