tests: run parts of the vmcheck testsuite
    
    Run the basic and layering-basic vmcheck tests on qcow2 Atomic Host
    images. It's full of hacks for now; I'd like to confirm first that there
    aren't any oversights that would prevent the pipeline from running it.
    
    Once we get it going, we can work on cleaning up and upstreaming the
    hacks to standard-test-roles, and run all the vmcheck tests.