Make sure builtin functions don't rely on __proto__.

This makes sure that none of the builtin functions rely on the __proto__
accessor which can now be monkey-patched by applications. Instead use a
separate %SetPrototype() intrinsic or object literals to do the job.

R=rossberg@chromium.org

Review URL: https://codereview.chromium.org/12385082

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@13815 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Also fix cast warnings on Win64

R=mstarzinger@chromium.org
BUG=

Review URL: https://codereview.chromium.org/12398011

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@13816 ce2b1a6d-e550-0410-aec6-3dcde31c8c00