Android: Replace emulation rotation crash workaround with proper fix

The workaround was added in 0446a58.

The underlying problem is that we must not destroy the surface
while the video backend is initializing, otherwise the video
backend may reference nullptr.

I've also cleaned up the logic for when to destroy the surface.
Note that the comment in EmulationFragment.java about only being
able to destroy the surface when emulation is running is not true
anymore (due to de632fc, it seems like).

Source/Core/Core/Core.h

@@ -56,6 +56,7 @@ bool WantsDeterminism();
 // [NOT THREADSAFE] For use by Host only
 void SetState(State state);
 State GetState();
+void WaitUntilDoneBooting();
 
 void SaveScreenShot(bool wait_for_completion = false);
 void SaveScreenShot(std::string_view name, bool wait_for_completion = false);