[TIMOB-26688] iOS: Proxy objects created in timers aren't released properly

Simplest case (iOS): Create an extremely simple app which just opens a controller containing a ListView with a headerView and a View inside that, and then close that controller again after a couple of seconds - the View inside the HeaderView is not destroyed / memory is not released, so the View remains, its proxy remains, the header proxy remains, the list proxy remains and the window proxy remains in memory... every time you reopen the controller the allocations grow until eventually the app freezes and refuses to respond. [Sample app attached - 'assets' folder is empty, as they're just the standard assets in any new project created via studio and take up over 13Mb so won't fit on the ticket!]