GH-113528: Slightly improve `pathlib.Path.glob()` tests for symlink loop handling (#113763)

Slightly improve `pathlib.Path.glob()` tests for symlink loop handling

When filtering results, ignore paths with more than one `linkD/` segment,
rather than all paths below the first `linkD/` segment. This allows us
to test that other paths under `linkD/` are correctly returned.