Cleanup FooSpace::VerifyObject and ElementsAccessor::Validate.

R=danno@chromium.org

Review URL: https://codereview.chromium.org/23273004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16259 ce2b1a6d-e550-0410-aec6-3dcde31c8c00