* array.c (ary_make_shared): shared ary as shady. Need more effort to
  make it normal object.
* array.c (rb_ary_modify): use RARRAY_PTR_USE() without WB because
  there are not new relations.
* array.c (ary_ensure_room_for_unshift): use RARRAY_RAWPTR() because
  there are not new relations.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42665 b2dd03c8-39d4-4d8f-98ff-823fe69b080e