selftests/landlock: Extend access right tests to directories

Make sure that all filesystem access rights can be tied to directories.

Rename layout1.file_access_rights to layout1.file_and_dir_access_rights
to reflect this change.

Cc: Shuah Khan <shuah@kernel.org>
Link: https://lore.kernel.org/r/20220506160820.524344-6-mic@digikod.net


Cc: stable@vger.kernel.org
Signed-off-by: Mickaël Salaün <mic@digikod.net>