Avoid bool to Oddball conversions by being lazy.

R=svenpanne@chromium.org
BUG=v8:2491

Review URL: https://chromiumcodereview.appspot.com/12459011

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@13869 ce2b1a6d-e550-0410-aec6-3dcde31c8c00