Injecting router service into EmberRouter infinitely recurses

Code sample:

```
// app/router.js
const Router = EmberRouter.extend({
  location: config.locationType,
  rootURL: config.rootURL,

  routerService: service('router'),

  init() {
    this.routerService.on('routeDidChange', () => {});
  }
});
```

Reproduction: https://github.com/ember-triage/emberjs-17791

P.S. Injecting `router` into `EmberRouter` also breaks.