selftest: Run test of how userPassword / crypt() style passwords are stored in quicktest

This ensures that the crypt_r()/crypt_rn()/crypt() behaviour is tested in all
the samba-o3 builds and so is checked on RHEL7 in GitLab CI.

https://bugzilla.samba.org/show_bug.cgi?id=14424

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Alexander Bokovoy <ab@samba.org>
(cherry picked from commit cabf873b)