remove redundant assignment of isDestroyed
[FEATURE ember-testing-triggerEvent-helper]

Adds `triggerEvent` testing helper to allow triggering of arbitrary
events on an element.
Merge pull request #3792 from rjackson/trigger_test_helper

[FEATURE ember-testing-triggerEvent-helper]
Merge pull request #3480 from Lowest0ne/remove-redundant-assignment

remove redundant assignment of isDestroyed
short-circuit inner loop if no properties are present.
Update to latest RSVP (80cec268).

A few of the changes:

* Added `Promise.cast`
* Added `Promise.finally`
* Added `RSVP.on('error', callback)`.

See full changes [here](https://github.com/tildeio/rsvp.js/compare/ae4abbccea971a7a7a0437d8275b6c5f1f21ff4c...80cec268a5ef91273b2dd6cd83c3d3d4f4d427df).
Merge pull request #3784 from rjackson/update_rsvp

Update to latest RSVP (80cec268).