[parrot/parrot] ca7bca: [pmc] StringBuilder.substr needs no WB

[GitHub]

  Branch: refs/heads/rurban/stringbuilder-gh1123
  Home:   https://github.com/parrot/parrot
  Commit: ca7bcaf898d8e1a2d32fe0a543f2e11a1aeb15a0
      https://github.com/parrot/parrot/commit/ca7bcaf898d8e1a2d32fe0a543f2e11a1aeb15a0
  Author: Reini Urban <rurban at cpanel.net>
  Date:   2015-01-21 (Wed, 21 Jan 2015)

  Changed paths:
    M src/pmc/stringbuilder.pmc

  Log Message:
  -----------
  [pmc] StringBuilder.substr needs no WB

GH #1123. 1.14% faster