InDetTrigAmbiguitySolver: Complain about misconfigured MT jobs.

The thread-safety checker was not properly checking calls to virtual functions. When that is fixed, we get a warning about the call to IPRDtoTrackMapExchange::setPRDtoTrackMap.

This is indeed not thread safe, and is supposed to be used only for backwards compatibility with run 2.

To resolve this, split out the non-thread-safe part into a separate function. We suppress the thread-safety checker warning in the call to it, but we also explicitly check and fail the job if we're running such a run 2 configuration with more than one thread.