Core::SetState() allow state to change without sending a callback.

Some state changes are meant to be near instantanoues, before switching to something else. By reporting ithe instant switch, the UI will flicker between states (pause/play button) and the debugger will unnecessarily update. Skipping the callback avoids these issues.

Source/Core/Core/Core.h

@@ -147,7 +147,7 @@ bool IsHostThread();
 bool WantsDeterminism();
 
 // [NOT THREADSAFE] For use by Host only
-void SetState(State state);
+void SetState(State state, bool report_state_change = true);
 State GetState();
 
 void SaveScreenShot();