remove commented out code in v8.h

TBR=dslomov@chromium.org
BUG=

Review URL: https://codereview.chromium.org/23676007

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16591 ce2b1a6d-e550-0410-aec6-3dcde31c8c00