Convert control loop tests over to simulated event loop

This makes it so that we properly only use ShmEventLoop for running in
realtime on a robot.  Very nice.

Change-Id: I46b770b336f59e08cfaf28511b3bd5689f72fff1
diff --git a/aos/events/simulated-event-loop_test.cc b/aos/events/simulated-event-loop_test.cc
index be52243..e987a11 100644
--- a/aos/events/simulated-event-loop_test.cc
+++ b/aos/events/simulated-event-loop_test.cc
@@ -17,6 +17,7 @@
   }
 
   void Run() override { event_loop_factory_.Run(); }
+  void Exit() override { event_loop_factory_.Exit(); }
 
   // TODO(austin): Implement this.  It's used currently for a phased loop test.
   // I'm not sure how much that matters.