Make new space iterable for --log-gc and --heap-stats options

R=hpayer@chromium.org
BUG=370827
TEST=test/mjsunit/regress/regress-370827.js
LOG=N

Review URL: https://codereview.chromium.org/272503005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21209 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Clean up Debugger::NotifyMessageHandler.

R=ulan@chromium.org

Review URL: https://codereview.chromium.org/276433004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21210 ce2b1a6d-e550-0410-aec6-3dcde31c8c00