Lock the prototype of internal classes.

Lock the prototype of internal classes.

Prototypes and their properties and methods are locked down to prevent fiddling with their operation, even if the build-in object leaks.

Made some built-in functions only work during bootstrapping.

Review URL: http://codereview.chromium.org/7799027

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9122 ce2b1a6d-e550-0410-aec6-3dcde31c8c00