test(cli): skip permission based tests under root & Windows
Permission-based tests expecting "Permission Denied" errors are invalid when run as root or on Windows. Adding mechanism to skip those tests:
- Guard in skip_if_root marker to only apply on POSIX.
- New skip_on_windows marker to skip these tests on Windows.
Signed-off-by: Deeptanshu Sekhri deeptanshu.sekhri@arm.com