Handle Xorg starting unusually slowly, but soft fail (#1622254)
    
    There seems to be a bug in Rawhide lately where, when our tests
    want to install a bare X and run Firefox on it, this takes an
    unusually long time to start up, with SELinux in enforcing mode.
    With SELinux in permissive mode it starts as fast as usual. This
    isn't a hard failure and we don't want it to block all later
    tests, so let's handle it and treat it as a soft fail.
    
    Signed-off-by: Adam Williamson <awilliam@redhat.com>