extend JobManager TestCase

I added a testcase to the JobManagerTest to test the deferring because of missing requirements (I had problems with the JobManager in #2031). It currently fails.

If I didn't misunderstood the JobManager logic, it could be fixed by removing the `return JobResult.DEFERRED;` in the JobConsumer file.
This is another bug I think.
The `int runIteration` wasn't increased if there is an catched exception and the requirements are still fullfilled...