This reverts commit f43bba8d597f511b6c6eeab77045f332ca6d906a.
Adding randomness has introduced a lot of flakiness in our ember-cli tests. We should fix those issues at the source. However, given the upcoming stable release, this randomness has been reverted so that the stable release includes a stable test suite. Having a stable test suite on stable will make backporting future commits much easier.