Revert "Implement zone-allocated types"

This reverts commit 4308974b16d1ee67d9f64d797c5ea64ffaab51df.

TBR=machenbach@chromium.org
BUG=

Review URL: https://codereview.chromium.org/133353005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@18545 ce2b1a6d-e550-0410-aec6-3dcde31c8c00