remove requires of core_ext/array/random_access that no longer exists

activerecord/test/cases/associations/eager_load_nested_include_test.rb

@@ -6,7 +6,6 @@
 require 'models/category'
 require 'models/categorization'
 require 'models/tagging'
-require 'active_support/core_ext/array/random_access'
 
 module Remembered
   extend ActiveSupport::Concern

activerecord/test/cases/named_scope_test.rb

 require "cases/helper"
-require 'active_support/core_ext/array/random_access'
 require 'models/post'
 require 'models/topic'
 require 'models/comment'