Merge pull request #14105 from twooster/fix-controller-tests

Fix controller test not resetting @_url_options

Conflicts:
	actionpack/CHANGELOG.md
Fix some validators when used on model instance

Now that Validator #setup is called from the initializer, we need a
reference to the model's class to be passed in to allow the validators
to continue functioning when used at the instance level.

Closes #14134.