Do a final pass freeing temporary memory when we quit.

Fixes https://github.com/libsdl-org/SDL/issues/10169

src/SDL.c

@@ -559,6 +559,8 @@ void SDL_Quit(void)
      */
     SDL_memset(SDL_SubsystemRefCount, 0x0, sizeof(SDL_SubsystemRefCount));
 
+    SDL_FlushEventMemory(0);
+
     SDL_CleanupTLS();
 
     SDL_FreeEnvironmentMemory();