Fix {get,set}ter-on-elements tests to run through all creation functions

setter-on-elements had the wrong length hardcoded in a for loop over the
creation functions (getter-on-elements had the right length, but seemed
worth future-proofing).

R=mvstanton@chromium.org

Review URL: https://codereview.chromium.org/643143005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24813 ce2b1a6d-e550-0410-aec6-3dcde31c8c00