Replace anchor point by translation and pivot point

Anchor point is deprecated and will eventually be removed from
Mutter's Clutter. Replace them by a combination of pivot point
and translation.

https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1334

js/ui/panel.js

@@ -675,7 +675,7 @@ class PanelCorner extends St.DrawingArea {
         let borderWidth = node.get_length('-panel-corner-border-width');
 
         this.set_size(cornerRadius, borderWidth + cornerRadius);
-        this.set_anchor_point(0, borderWidth);
+        this.translation_y = -borderWidth;
     }
 });