ipa-kdb: fix crash in MS-PAC cache init code
    
    When initializing UPN suffixes, we calculate their sizes and didn't use
    the right variable to allocate their size. This affects us if there are
    more than one UPN suffix available for a trust due to memory corruption
    while filling in sizes.
    
    Add unit test for multiple UPN suffixes.
    
    Fixes: https://pagure.io/freeipa/issue/8566
    
    Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
    Reviewed-By: Rob Crittenden <rcritten@redhat.com>
    Reviewed-By: Robbie Harwood <rharwood@redhat.com>
    Reviewed-By: Rob Crittenden <rcritten@redhat.com>
    Reviewed-By: Robbie Harwood <rharwood@redhat.com>