GeezerVison

Fix tests in test_compileall, test_import, test_importlib, test_py_compile, and test_inspect to neutralize PYTHONPYCACHEPREFIX
(cherry picked from commit 564c58c)

Co-authored-by: Jiucheng(Oliver) [email protected]

• Issue: Some tests fail when __pycache__ prefix is set #151626

Manual backport notes (3.14)

miss-islington could not cleanly backport this to 3.14 due to a conflict in Lib/test/test_inspect/test_inspect.py. The 3.14 branch predates the python -m inspect --details CLI test refactor that exists on main/3.15 (it still has the simpler TestMain.test_details rather than TestModuleCLI with the test_details_option_with_*/test_get_cli_details_for_* suite).

The fix was translated to 3.14's dialect:

• The _expected_cached() helper was added verbatim from the original PR, in TestMain.
• It was applied to the single TestMain.test_details, replacing the environment-dependent module.__spec__.cached check. The redundant self.assertIn(module.__cached__, output) line (same pyc path, and itself failing under PYTHONPYCACHEPREFIX) was dropped.
• None of the main-only test machinery was pulled in.

The other four files and the NEWS entry cherry-picked cleanly (identical hunks to the original).

Verified: test_inspect, test_compileall, test_import, test_importlib, and test_py_compile all pass both normally and with PYTHONPYCACHEPREFIX set; make patchcheck is clean.