Match max property descriptor length to corresponding bit fields

BUG=v8:3010
R=verwaest@chromium.org
LOG=N

Review URL: https://codereview.chromium.org/72333004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@17823 ce2b1a6d-e550-0410-aec6-3dcde31c8c00