[Ember] Revisiting same route with no `didRender` does not set focus.

If you navigate anywhere that maintains the same route hierarchy (read: does not trigger the `insert` top-down behavior) you'll receive the `render` bottom-up behavior. If the result of the route change does not actually trigger the `didRender` lifecycle hook at the leaf-most-node it will result in focus being set to the closest `self-focusing` component whose `didRender` hook fired.

This happens, for example, when the content is completely static.

Reproducible in the existing test app. After loading:
- Click "About"
- Click "About" again.
- Observe no focus state.

Alternatively:
- Click "Topics"
- Click "Components"
- Click "Components" again.
- Observe focus state set at the "Topics" level.