Includes a few minor performance improvements:
* In the `nextContext` instruction we assign a new LView to the `LFrame.contextLView` and then we immediately look it up to get its context. We don't need to do that since we know the view that was assigned already.
* Removes the default value for the `level` parameter of `nextContextImpl` because it generates more code in es5 and is internal-only.
* Removes the default parameter from `setActiveHostElement` since it generates extra code and it's an internal function.
* Makes a check in `setElementExitFn` more strict since we're guaranteed for the value to match the type.
PR Close#34183
a295255e58