Remove `require 'active_support'` from individual modules

Let users require `active_support` before loading any ActiveSupport modules
http://guides.rubyonrails.org/active_support_core_extensions.html

activesupport/lib/active_support/i18n_railtie.rb

-require "active_support"
 require "active_support/file_update_checker"
 require "active_support/core_ext/array/wrap"
 

activesupport/lib/active_support/railtie.rb

-require "active_support"
 require "active_support/i18n_railtie"
 
 module ActiveSupport

activesupport/lib/active_support/time.rb

-require 'active_support'
-
 module ActiveSupport
   autoload :Duration, 'active_support/duration'
   autoload :TimeWithZone, 'active_support/time_with_zone'