Pass in HWND_MESSAGE as parent in qt_create_internal_window()

static HWND qt_create_internal_window(const QEventDispatcherWin32 *eventDispatcher)
...
HWND wnd = CreateWindow(wc.lpszClassName, // classname
wc.lpszClassName, // window name
0, // style
0, 0, 0, 0, // geometry
0, // parent   //HWND_MESSAGE should be used instead here
0, // menu handle
qWinAppInst(), // application
0); // windows creation data.