Added a reference to SDL_Direct3D9GetAdapterIndex to SDL_test_common.c so SDL will fail to compile if the new symbol isn't included properly.
CR: Jorgen
If the app is in landscape mode and the user presses the power button, a pause
is followed immediately by a surfaceChanged event because the lock screen
is shown in portrait mode. This triggers a "false" resume.
So, we just pause and resume following the onWindowFocusChanged events.
Also, wait for SDL_APP_WILLENTERBACKGROUND and SDL_APP_DIDENTERBACKGROUND before
blocking the event pump.