The phase_zone of CompilationInfo is intended for local allocations that
are freed at the end of the phase.

R=danno@chromium.org
BUG=

Review URL: https://codereview.chromium.org/17573003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15294 ce2b1a6d-e550-0410-aec6-3dcde31c8c00