Include the initial definitions for parameters on input to the
function, and the initial definition of stack-allocated locals as
undefined.

Review URL: http://codereview.chromium.org/1155006

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4206 ce2b1a6d-e550-0410-aec6-3dcde31c8c00