windows: Reviewed and ported a bunch of Q_OS_WIN_OLD usages

Those are fine. Will tackle the difficult ones next.

examples/qtquick/customtitlebar/main.cpp

@@ -36,7 +36,7 @@ CustomViewFactory::~CustomViewFactory() = default;
 
 int main(int argc, char *argv[])
 {
-#ifdef Q_OS_WIN_TODO
+#ifdef Q_OS_WIN
     QGuiApplication::setAttribute(Qt::AA_UseOpenGLES);
 #endif
     QGuiApplication app(argc, argv);