Add a checkbox to raise on deprecation to the tests

![](https://api.monosnap.com/image/download?id=XykMzGNnBTxgGdTUSGcW1IU7kvgaer)
![](http://stream1.gifsoup.com/view/338920/mister-trololo-sez-hi-o.gif)

I [complained about deprecation noise in the tests](https://github.com/emberjs/ember.js/pull/5388#issuecomment-52389452), but really there isn't an easy way to see that you have caught all occurrences of a deprecated behavior. This is a start, and once the notices are clean we can maybe add this flag to the test runs on CI.

Refs #4748