class.c: from the origin class

* class.c (rb_obj_singleton_methods): collect methods from the origin
  class.  [ruby-core:53207] [Bug #8044]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39744 b2dd03c8-39d4-4d8f-98ff-823fe69b080e