[1.22] Normally skip tests that are not expected to succeed

If a test is not expected to succeed, then running it could be considered to be a waste of resources, particularly if the failure might manifest as an indefinite hang (see !11 (merged)), or if the test is likely to dump core and trigger "expensive" crash-reporting mechanisms like systemd-coredump, corekeeper, abrt or apport.

Skip the tests that are expected to fail. They can still be requested via an environment variable, which can be set after fixing a bug to check which tests are now passing