Add basic ACL consistency test case.

This test case is used to detect and reproduce a customer issue we're
seeing where the new .get_acl() method API and underlying changes in
el9_6+ are causing ACL cache fetching to return inconsistent results,
which shows as missing ACLs on directories.

This particular sequence is consistent enough that it warrants making
it into a specific test.

Signed-off-by: Auke Kok <auke.kok@versity.com>

tests/sequence

@@ -2,6 +2,7 @@ export-get-name-parent.sh
 basic-block-counts.sh
 basic-bad-mounts.sh
 basic-posix-acl.sh
+basic-acl-consistency.sh
 inode-items-updated.sh
 simple-inode-index.sh
 simple-staging.sh