Heap profiler clean-up: remove dead code

R=yangguo@chromium.org, loislo@chromium.org
LOG=N
BUG=Non

Review URL: https://codereview.chromium.org/681333003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24954 ce2b1a6d-e550-0410-aec6-3dcde31c8c00