Need tests to cover the following scenario and it's permutations:
<html><body><script type="text/javascript">
function Foo() {}
var p = new Foo();
p.z = 0;
var numZCalls = 100;
var zGetCalls = 0;
var zSetCalls = 0;
Object.defineProperty(Foo.prototype, "z",
{ get: function () { zGetCalls++; return 0; },
set: function (value) { zSetCalls++;},
configurable: false });
p = new Foo();
for (var i = 0; i < numZCalls; i++) {
p.z += 1;
}
alert(zGetCalls===numZCalls);
alert(zSetCalls===numZCalls);
</script></body></html>