Cleanup 'container lookup is normalized' test

This addresses code discussion in [#2350](https://github.com/emberjs/ember.js/pull/2350#discussion_r3542109).

![LWkwEfK](https://f.cloud.github.com/assets/341877/310783/6fbfd1b2-9726-11e2-94ab-e7637784956d.gif)