NOT FOR MERGE: Log a warning if the simulator appears to be in an inconsistent state. (refs #147)

When builds hang, we sometimes see other failures like the simulator
failing to rotate to portrait orientation. We now log a warning on launch
if the simulator fails to respond to such manipulation. If we see that such
failures are indeed a reliable indicator that the run will hang, we'll amend this
to have Subliminal abort the tests on startup and `subliminal-test` retry.