Merge pull request #5014 from castlerock/fix_build_PR_5001

fix build #5001, model reply is required in cases/primary_keys_test too! for isolated test

activerecord/test/cases/primary_keys_test.rb

 require "cases/helper"
 require 'models/topic'
+require 'models/reply'
 require 'models/subscriber'
 require 'models/movie'
 require 'models/keyboard'