Update constant pool correctly when resuming a generator

This CL depends on the following CLs landing first:
  https://codereview.chromium.org/188063002/
  https://codereview.chromium.org/190793002/

R=ulan@chromium.org

Review URL: https://codereview.chromium.org/190823002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20012 ce2b1a6d-e550-0410-aec6-3dcde31c8c00