The intention is to store enough scope information for the debugger to
handle stack allocation of block scoped variables introduced by
http://codereview.chromium.org/7860045/ .

This CL is based on
http://codereview.chromium.org/7904008/ .

Review URL: http://codereview.chromium.org/7979001

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9673 ce2b1a6d-e550-0410-aec6-3dcde31c8c00