Minor cleanup in ChainNode.unchain.

Do not reassign passed in variable. Makes debugging quite painful.
[BUGFIX beta] Sync backburner
[BUGFIX beta] Use run.join in EventDisaptcher

This is required so that synchronous events (like focus) do not spawn
a nested run loop.
Merge pull request #9494 from mmun/join-bubble-event

Sync backburner & Use run.join in EventDisaptcher
Merge pull request #9493 from rwjblue/minor-cleanup

Minor cleanup in ChainNode.unchain.
Split up single line functions in Ember.Route.

Makes debugging much easier (allows you to put a breakpoint on the
actual body of the function).
Merge pull request #9499 from rwjblue/split-single-line-functions

Split up single line functions in Ember.Route.