Refactor to remove DrawOnce module

We were doing extra work that could be pushed off to Integration test
and SharedRoutes. Creating an extra module isn't necessary when those
are created by their respective classes.

actionpack/test/abstract_unit.rb

@@ -63,42 +63,21 @@ def env
 
 SharedTestRoutes = ActionDispatch::Routing::RouteSet.new
 
+SharedTestRoutes.draw do
+  get ':controller(/:action)'
+end
+
 module ActionDispatch
   module SharedRoutes
     def before_setup
       @routes = SharedTestRoutes
       super
     end
   end
-
-  # Hold off drawing routes until all the possible controller classes
-  # have been loaded.
-  module DrawOnce
-    class << self
-      attr_accessor :drew
-    end
-    self.drew = false
-
-    def before_setup
-      super
-      return if DrawOnce.drew
-
-      SharedTestRoutes.draw do
-        get ':controller(/:action)'
-      end
-
-      ActionDispatch::IntegrationTest.app.routes.draw do
-        get ':controller(/:action)'
-      end
-
-      DrawOnce.drew = true
-    end
-  end
 end
 
 module ActiveSupport
   class TestCase
-    include ActionDispatch::DrawOnce
     if RUBY_ENGINE == "ruby" && PROCESS_COUNT > 0
       parallelize_me!
     end
@@ -119,8 +98,6 @@ def call(env)
 end
 
 class ActionDispatch::IntegrationTest < ActiveSupport::TestCase
-  include ActionDispatch::SharedRoutes
-
   def self.build_app(routes = nil)
     RoutedRackApp.new(routes || ActionDispatch::Routing::RouteSet.new) do |middleware|
       middleware.use ActionDispatch::ShowExceptions, ActionDispatch::PublicExceptions.new("#{FIXTURE_LOAD_PATH}/public")
@@ -136,6 +113,10 @@ def self.build_app(routes = nil)
 
   self.app = build_app
 
+  app.routes.draw do
+    get ':controller(/:action)'
+  end
+
   # Stub Rails dispatcher so it does not get controller references and
   # simply return the controller#action as Rack::Body.
   class StubDispatcher < ::ActionDispatch::Routing::RouteSet::Dispatcher