* Add repro for 2489
- Repo steps are to swap to the TabbedPage root; if the tabs are still visbile, test has passed.
- Also add Preserve attribute to the core test pages so we can test with the Android linker on.
* [Android] Add note to remind us where the renderers are registered
* [iOS] Switch to loading renderers via RenderWithAttribute
* [Core] Ensure that the most specific renderer is returned by Registrar.GetHandlerType
fixes#2489
* [Core] Prevent insane loop
* implement review feedback
