when Object.isExtensible(o) === false

Added corresponding tests

ES5 description: http://es5.github.com/#x11.13.1

Related issue: http://code.google.com/p/v8/issues/detail?id=1901

Contributed by ioseb.dzmanashvili@gmail.com

BUG=
TEST=

Review URL: https://chromiumcodereview.appspot.com/9429002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10783 ce2b1a6d-e550-0410-aec6-3dcde31c8c00