add ARM test to conf_test_suites
    
    This adds ARM test ("default install") to conf_test_suites.
    It also works around bug, solved in https://github.com/os-autoinst/openQA/pull/673
    - without this patch, destination file cannot have different filename, so I removed
    setting KERNEL and INITRD to different values.
    
    Differential Revision: https://phab.qadevel.cloud.fedoraproject.org/D852