tests/acceptance: Fix race conditions in s390x tests & skip fedora on gitlab-CI

tests/acceptance: Fix race conditions in s390x tests & skip fedora on gitlab-CI

There was a race condition in the first test where there was already the
"crw" output in the dmesg, but the "0.0.4711" entry has not been created
in the /sys fs yet. Fix it by waiting until it is there.

The second test has even more problems on gitlab-CI. Even after adding some
more synchronization points (that wait for some messages in the "dmesg"
output to make sure that the modules got loaded correctly), there are still
occasionally some hangs in this test when it is running in the gitlab-CI.
So far I was unable to reproduce these hangs locally on my computer, so
this issue might take a while to debug. Thus disable the 2nd test in the
gitlab-CI until the problems are better understood and fixed.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Tested-by: Willian Rampazzo <willianr@redhat.com>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Message-Id: <20210108185645.86351-1-thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>