selftests/landlock: Add tests for unknown access rights

commit c56b3bf566da5a0dd3b58ad97a614b0928b06ebf upstream.

Make sure that trying to use unknown access rights returns an error.

Cc: Shuah Khan <shuah@kernel.org>
Link: https://lore.kernel.org/r/20220506160820.524344-5-mic@digikod.net


Cc: stable@vger.kernel.org
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>