wayland: Don't forget to reapply margins

When using the saved size because the compositor
told us to, we were forgetting to readd the margins.

The visible symptom of this was the window getting
smaller every time we went to tiled state and back.

gdk/wayland/gdksurface-wayland.c

@@ -1354,6 +1354,11 @@ gdk_wayland_surface_configure_toplevel (GdkSurface *surface)
           /* Save size for next time we get 0x0 */
           _gdk_wayland_surface_save_size (surface);
         }
+      else
+        {
+          width += impl->margin_left + impl->margin_right;
+          height += impl->margin_top + impl->margin_bottom;
+        }
 
       gdk_wayland_surface_resize (surface, width, height, impl->scale);
     }