Drop some unused code

Bonus: fix bitrot in (disabled) Hydrogen-BCH

R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/623513002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24392 ce2b1a6d-e550-0410-aec6-3dcde31c8c00