Removal require again from tests.

activesupport/test/callback_inheritance_test.rb

@@ -1,6 +1,5 @@
 require 'abstract_unit'
 require 'test/unit'
-require 'active_support'
 
 class GrandParent
   include ActiveSupport::Callbacks

activesupport/test/callbacks_test.rb

@@ -1,6 +1,5 @@
 require 'abstract_unit'
 require 'test/unit'
-require 'active_support'
 
 module CallbacksTest
   class Phone

activesupport/test/file_update_checker_test.rb

@@ -1,6 +1,5 @@
 require 'abstract_unit'
 require 'test/unit'
-require 'active_support'
 require 'fileutils'
 
 MTIME_FIXTURES_PATH = File.expand_path("../fixtures", __FILE__)

activesupport/test/flush_cache_on_private_memoization_test.rb

@@ -1,5 +1,4 @@
 require 'abstract_unit'
-require 'active_support'
 require 'test/unit'
 
 class FlashCacheOnPrivateMemoizationTest < Test::Unit::TestCase