Properly process arrays with overridden prototype in various Array's functions.

Properly process arrays with overridden prototype in various Array's functions.

Bailout to JS Array builtins if array's prototype is different from
Array.prototype.  Otherwise there might be inherited elements coming
from this prototype.

Review URL: http://codereview.chromium.org/2037008

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4649 ce2b1a6d-e550-0410-aec6-3dcde31c8c00