Revert "Extract record array responsibility"

This reverts commit 83419415a0c3d5521cf46b3b23525a72a650106e.

Conflicts:
	packages/ember-data/lib/system/store.js
RESTAdapter : Convert errors object returned with a 422 in an Ember Object
RESTAdapter : Improve errors 422 (validation) for embedded records

When an error 422 is received, all embedded records will be send to the invalid state
When an invalid record is modified, it will became valid. His parents will became valid too if all of their embedded records are valid.
Errors set on embedded object is an Ember Object
Fix all records array load state

The all record array which is returned by `App.Model.find()` will
not be flagged as loaded before the adapter populate the array with the
query result
Clean record errors when rollback an invalid record
Keep errors after 422 response event if they do not match an attribute name
Removed tests because of conflicts
Updated _parentTree on RestAdapter to use new reference format
Removed too early cleaning of relationships information on transaction

With these lines, when we rollback a transaction after commited it, the associated
relationships are not properly rollback as the relationships information on the
transaction are lost.