runnermanager: Remove logic for deferred runs

This logic came into play when a runner's match is run, but the runner has not finished matching. In this case the match would be run after the runner has finished matching.

This could make sense if the runner has to set some internal state first, but the matches can contain their own data and the AbstractRunner::match method is not thread safe anyways. Also the method docs strictly advise against using a state which gets modified in the match method.