[libcxx] [test] Don't leave test dirs behind in fs.op.current_path on Windows

Fix nesting of static_env and CWDGuard, restore the cwd (with
CWDGuard) before cleaning up the static_env.

Previously, every test run left 2 directories behind in the temp dir.

Differential Revision: https://reviews.llvm.org/D98954

GitOrigin-RevId: 4c402ae880cf9a922f0d95e637a596792e05ac1e
1 file changed