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/shm-event-loop.h b/aos/events/shm-event-loop.h
index 24cd909..5db8319 100644
--- a/aos/events/shm-event-loop.h
+++ b/aos/events/shm-event-loop.h
@@ -50,8 +50,8 @@
           ::std::chrono::seconds(0)) override;
 
   void OnRun(::std::function<void()> on_run) override;
-  void Run() override;
-  void Exit() override;
+  void Run();
+  void Exit();
 
   // TODO(austin): Add a function to register control-C call.