Ensure that all tests run on CI
It happens frequently that a job stop in the middle of tests without being marked as failing. It is confusing and makes the "Merge when pipeline succeeds" feature useless since we can't trust the pipeline status.
We should start by adapting https://forge.extranet.logilab.fr/cubicweb/relaunch_broken_ci_jobs/ to relaunch succeeding jobs which didn't realy complete.