Merge pull request #370 from rwjblue/micro-task-next-tick

Allow internal `nextTick` utility to use microtasks when possible.

addon-test-support/@ember/test-helpers/-utils.js

@@ -1,6 +1,7 @@
 import { Promise } from 'rsvp';
 
-export const nextTick = setTimeout;
+export const nextTick =
+  typeof Promise === 'undefined' ? setTimeout : cb => Promise.resolve().then(cb);
 export const futureTick = setTimeout;
 
 /**