and make window.{Infinity,NaN,undefined} read-only as per ES5

BUG=89490
TEST=mjsunit/const-redecl.js, mjsunit/undeletable-functions.js, es5conform, sputnik

Review URL: http://codereview.chromium.org/7811015

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9299 ce2b1a6d-e550-0410-aec6-3dcde31c8c00