Trigger didLoad event in the `AdapterPopulatedRecordArray` at the end of the runloop

Include an integration test to show the expected behaviour.

Currently, some events in the models have been delayed with `Em.run.once`, however the events in the recordArray has  has not been delayed, so records and recordArray could be in an inconsistent state, which originates the following exception:

__Uncaught Error: Attempted to handle event loadedData on App.Person:ember244:1 while in state rootState.deleted.uncommitted. Called with {}__

Triggering the `didLoad` event of the `AdapterPopulatedRecordArray` at the end of the runLoop fixed this case.