This allows to unclutter logging-related code.
I also fixed compilation issues with 'profilingsupport=off'.

Review URL: http://codereview.chromium.org/1317003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4285 ce2b1a6d-e550-0410-aec6-3dcde31c8c00