The tests for calls of the LockListener from a JobManager only validate
whether the JobManager is not waiting for a lock in the end. They do not
validate whether it has been waiting for a lock at all. The jobs may not
be running anymore when JobManager.join is called, such that no lock
will be acquired at all.
- Add possibility to explicitly define when a TestJob should end rather
  than trusting in proper timing behavior with a defined Job run time
- Improve tests for calling LockListener when calling join on JobManager