Set eager load option in "make_basic_app" for railties tests

Avoid output with config option not set when running some tests.

railties/test/isolation/abstract_unit.rb

@@ -136,6 +136,7 @@ def make_basic_app
       require "action_controller/railtie"
 
       app = Class.new(Rails::Application)
+      app.config.eager_load = false
       app.config.secret_token = "3b7cd727ee24e8444053437c36cc66c4"
       app.config.session_store :cookie_store, :key => "_myapp_session"
       app.config.active_support.deprecation = :log