Fixed spec violation of storing to length of a frozen object.

BUG=chromium:350890
LOG=N
R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/196653015

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20005 ce2b1a6d-e550-0410-aec6-3dcde31c8c00