Sometimes the serial output gets lost.
This doesn't happen constantly.
`COMMAND ; echo 123123-$?- > /dev/ttyS0`
and the test will fail with:
# wait_serial expected: qr/(?^:123123-\d+-)/
even when the *COMMAND* was executed without any issues. There's no entry in the serial0.txt file.
For now only i noticed in x86_64.
This happened in the test: https://openqa.suse.de/tests/1114687#step/piglit/14