wayland/surface: Don't double scale when getting absolute coordinates

The actor is already in surface coordinate space, so we should not scale
with the buffer scale to transform surface coordinates to stage
coordinates.

This bug causes input method using wayland text-input protocol to
receive wrong cursor location. Reproduced in ibus (when candidate
window is open) with scaling factor other than 1.

This commit also fixes pointer confinement.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/915

src/wayland/meta-wayland-surface.c

@@ -1647,8 +1647,8 @@ meta_wayland_surface_get_absolute_coordinates (MetaWaylandSurface *surface,
   ClutterActor *actor =
     CLUTTER_ACTOR (meta_wayland_surface_get_actor (surface));
   ClutterVertex sv = {
-    .x = sx * surface->scale,
-    .y = sy * surface->scale,
+    .x = sx,
+    .y = sy,
   };
   ClutterVertex v = { 0 };