tests: Mark failing tests as failing
    
    Some tests from installation suite fail.
    The issues are:
    
    * ipa-replica-install --setup-kra if first KRA in topology fails
      https://pagure.io/freeipa/issue/7008
    
    * Third KRA installation in topology fails
      https://pagure.io/freeipa/issue/7220
    
    This patch marks those tests as failing.
    
    Signed-off-by: Petr Čech <pcech@redhat.com>
    Reviewed-By: Tibor Dudlak <tdudlak@redhat.com>