Each CompilationPhase has its own zone, used for phase local
allocations. The zone of CompilationInfo should only be used
for non phase local allocations.

R=danno@chromium.org
BUG=

Review URL: https://codereview.chromium.org/18022002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15352 ce2b1a6d-e550-0410-aec6-3dcde31c8c00