Remove feature flags for 'ember-routing-didTransition-hook'.
Remove feature flags for 'ember-routing-loading-error-substates'.
Remove feature flags for 'ember-runtime-sortBy'.
Remove feature flags for 'container-renderables'.
Remove feature flags for 'link-to-non-block'.
Remove feature flags for 'reduceComputedSelf'.
Components are lazily looked up.
Fix incorect removal of 'ember-routing-loading-error-substates'.
[FEATURE ember-testing-routing-helpers]

Adds `currentRouteName`, `currentPath`, and `currentURL` testing helpers.
Merge pull request #3711 from rjackson/add_route_testing_helpers

[FEATURE ember-testing-routing-helpers]
Merge pull request #3787 from rjackson/remove_stable_feature_flags

Remove feature flags that are included in 1.2.0.