pytest: test that _glue.crypt works

pytest: test that _glue.crypt works

The test vectors were generated via Python 3.10 crypt module, which
directly wraps crypt(3), which in this case is from glibc 2.39-0ubuntu8.3.

We mainly test the sha256 and sha512 vectors, which seems to be all we
use, and which are said to be widely supported.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15756

Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Andreas Schneider <asn@samba.org>