Windows: Fix bug where windows stopped painting after a restore.

This is an improvement over 6800728d where we only fixed it if
the window was in "normal" state (Qt::WindowNoState) before
minimizing.

With this patch, if the window was previously maximized or
full-screen it will also get the expose events when being
restored.

Change-Id: I4a30423145e0999c5d0a5ee2a989730b83f4e3f2
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Nicolas Arnaud-Cormos <nicolas@kdab.com>

src/plugins/platforms/windows/qwindowswindow.cpp

@@ -1500,6 +1500,8 @@ void QWindowsWindow::handleWindowStateChange(Qt::WindowState state)
         handleHidden();
         QWindowSystemInterface::flushWindowSystemEvents(); // Tell QQuickWindow to stop rendering now.
         break;
+    case Qt::WindowMaximized:
+    case Qt::WindowFullScreen:
     case Qt::WindowNoState: {
         // QTBUG-17548: We send expose events when receiving WM_Paint, but for
         // layered windows and transient children, we won't receive any WM_Paint.