fix(tests): use shutil.which instead of Unix 'which', skip Unix 'find' tests on Windows

[iamiskender]

What

tests/tools/test_search_hidden_dirs.py collection crashed on native Windows with FileNotFoundError: [WinError 2] — the TestRipgrepAlreadyExcludesHidden skipif condition called subprocess.run(["which", "rg"], ...), and which doesn't exist on Windows.

TestFindExcludesHiddenDirs also relies on the Unix find command via shell=True, which resolves to Windows' incompatible FIND.EXE and fails.

Fix

• Replaced the which-based ripgrep detection with shutil.which("rg"), which works cross-platform.
• Marked TestFindExcludesHiddenDirs with @pytest.mark.skipif(sys.platform == "win32", ...) since the find-based assertions are Unix-specific.

Testing

pytest tests/tools/test_search_hidden_dirs.py -v on native Windows — 8 passed, 2 skipped (previously: collection error, 0 tests ran).

[alt-glitch]

This was generated by AI during triage.

Duplicate of #42872: both replace the Unix which probe and skip the Unix-only find tests on Windows. #42872 additionally covers the adjacent grep-only test class.

[iamiskender]

Ack, thanks — closing as duplicate of #42872.

[iamiskender]

Ack, thanks — closing as duplicate of #42872.