The code used the size of the internal class in an inconsistent
way. It should simply compute and work with the old internal
class size, as that reflects the old object layout.
[ChangeLog][QtQml] Fix assertion when deleting properties of JS objects
Task-number: QTBUG-54589
Change-Id: Ie3db70437e780215d08a1a96491db75f8b859754
Reviewed-by: Robin Burchell <robin.burchell@viroteck.net>
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>
Lars Knoll