Put back the require

Author: rafaelfranca

activesupport/test/core_ext/object/json_gem_encoding_test.rb

@@ -40,7 +40,7 @@ def to_json(*)
 
   private
     def require_or_skip(file)
-      force_skip("'#{file}' was already loaded")
+      require(file) || force_skip("'#{file}' was already loaded")
     end
 
     def assert_same_with_or_without_active_support(subject)