Fix prompt colorization test's setup

Author: st0012

railties/test/commands/console_test.rb

@@ -59,7 +59,8 @@ def test_console_defaults_to_IRB
   end
 
   def test_prompt_env_colorization
-    irb_console = Rails::Console::IRBConsole.new(app)
+    app = build_app(nil)
+    irb_console = Rails::Console.new(app).console
     red = "\e[31m"
     green = "\e[32m"
     clear = "\e[0m"