* object.c (mutable_obj_clone): `Kernel#clone` should not copy
  FL_USER* flags because they are copied unexpectedly.
  Unexpected copy will break internal data consistency.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63912 b2dd03c8-39d4-4d8f-98ff-823fe69b080e