The test does a clutter_actor_set_scale_full() call that only updates
the scale center (i.e. no changes to scale-x/y), but expects to receive
notifications of actor scale changes.
Since "Revert "Revert "ClutterActor: Optimize away idempotent
scale/position updates"" these are optimized away, so just drop the
assumption.
697aeae2ad