LibCore: Signal an event to queue a wake completion packet on Windows

The initial IOCP event loop implementation adjusted wake() to manually
queue a completion packet onto the current threads IOCP. This caused
us to now be dependent on the current threads IOCP, when the previous
behaviour did not depend on any data from the thread that was waking
the event loop.

Restoring that old behaviour allows https://hardwaretester.com/gamepad
to be loaded again.

Libraries/LibCore/EventLoopImplementationWindows.h

@@ -48,7 +48,8 @@ private:
     bool m_exit_requested { false };
     int m_exit_code { 0 };
 
-    void const* m_wake_completion_key;
+    // The wake event handle of this event loop needs to be accessible from other threads.
+    void*& m_wake_event;
 };
 
 using EventLoopManagerPlatform = EventLoopManagerWindows;