Restart When script correctly when BroadcastWait is sent

A `When` script was not correctly restarted if a `BroadcastWait` was sent. See regression tests in `BroadcastActionTest.java` and `BroadCastReceiverRegressionTest.java` for examples.

This fixes issue #876 

Successful Jenkins testrun: ~~[1241](https://jenkins.catrob.at/job/Catroid-Multi-Job-Custom-Branch/1241/)~~ [1260](https://jenkins.catrob.at/job/Catroid-Multi-Job-Custom-Branch/1260/)