Refactors JSGraph to ensure that the zone operators are created in
can be different from the Graph's zone.

R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/553873002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23804 ce2b1a6d-e550-0410-aec6-3dcde31c8c00