window: Remove call to gtk_widget_reset_rc_styles()

First of all, that call is deprecated. Second, we don't have RC styles
anymore. Third, what that function does today is invalidate style
contexts, but that happens automatically when setting the screen on the
style context later.

So this function is completely unnecessary.

gtk/gtkwindow.c

@@ -9779,7 +9779,6 @@ gtk_window_set_screen (GtkWindow *window,
 
   gtk_window_free_key_hash (window);
   priv->screen = screen;
-  gtk_widget_reset_rc_styles (widget);
   if (screen != previous_screen)
     {
       if (previous_screen)