Failing test for synchronous hasMany on the fixture adapter

A failing test for http://discuss.emberjs.com/t/whats-up-with-ds-hasmany/2934/6, probably http://discuss.emberjs.com/t/has-many-relationships-in-the-fixture-adapter/2512/3 and several other sad-sounding cases.

Synchronous `hasMany` relationships seem broken on the fixture adapter.