Currenly the constructor like this:
function f() {
  this.a = 0;
  this.a = 1;
  this.a = 2;
}
creates a map with duplicate desciptors which is bad in many ways.


Review URL: http://codereview.chromium.org/3434004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5476 ce2b1a6d-e550-0410-aec6-3dcde31c8c00