[FEATURE] Revert ember-routing-will-change-hooks
[FEATURE] Revert ember-routing-handlebars-action-with-key-code
[FEATURE] Revert ember-runtime-item-controller-inline-class.
[FEATURE] Revert event-dispatcher-can-disable-event-manager.
[FEATURE ember-routing-transitioning-classes] namespace classes

Use .ember-transitioning-in and .ember-transitioning-out
instead of non-ember-namespaced classes.
Merge pull request #9984 from rwjblue/revert-features

Revert features that are no longer in the proper direction.
[FEATURE ember-routing-transitioning-classes] enable this feature
Merge pull request #9987 from machty/ember-transitioning-in

[FEATURE ember-routing-transitioning-classes] namespace classes
Stream-based shouldDisplay checking

Closes #9895.