Implement zone-allocated types

More template magic FTW.

R=titzer@chromium.org
BUG=

Review URL: https://codereview.chromium.org/103743004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@18543 ce2b1a6d-e550-0410-aec6-3dcde31c8c00