testing/testcase: include partition dump when setup class fail

Sometimes instanciation fail because some service do not start and the
"check port listening" promises fail. In this case, it's very important
to also have the partition content to see what's in the log files.
.gitlab-ci.yml not found in this commit
Status Job ID Name Coverage
failed SlapOS.SoftwareReleases.IntegrationTest-Jerome-WIP