testgtk: Fix the scrolledwindow test

We need to expand here, otherwise things look wrong.

tests/testgtk.c

@@ -2791,6 +2791,8 @@ create_scrolled_windows (GtkWidget *widget)
       gtk_window_set_title (GTK_WINDOW (window), "dialog");
 
       scrolled_window = gtk_scrolled_window_new (NULL, NULL);
+      gtk_widget_set_hexpand (scrolled_window, TRUE);
+      gtk_widget_set_vexpand (scrolled_window, TRUE);
       gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (scrolled_window),
 				      GTK_POLICY_AUTOMATIC,
 				      GTK_POLICY_AUTOMATIC);