with encoding propagation.
  (extract_range): use str_new.
  (extract_beg_len): ditto.
  (strscan_peek): ditto.
  (strscan_rest): ditto.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@14772 b2dd03c8-39d4-4d8f-98ff-823fe69b080e