Turn canonicalization into a proper HPhase.

R=dslomov@chromium.org

Review URL: https://codereview.chromium.org/18758003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15613 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Implemented lazy sweeping of new space.

BUG=
R=titzer@chromium.org

Review URL: https://codereview.chromium.org/18998004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15616 ce2b1a6d-e550-0410-aec6-3dcde31c8c00