Use the correct model in the test

This was using a model without a default scope what made the test don't
break anymore if the code is removed.

activerecord/test/models/post.rb

@@ -78,7 +78,7 @@ def greeting
   has_many :comments_with_extend_2, extend: [NamedExtension, NamedExtension2], class_name: "Comment", foreign_key: "post_id"
 
   has_many :author_favorites, through: :author
-  has_many :author_favorites_with_scope, through: :author, class_name: "AuthorFavorite", source: "author_favorites"
+  has_many :author_favorites_with_scope, through: :author, class_name: "AuthorFavoriteWithScope", source: "author_favorites"
   has_many :author_categorizations, through: :author, source: :categorizations
   has_many :author_addresses, through: :author
   has_many :author_address_extra_with_address,