Incorrect iteration order of deleted and re-assigned properties.

Using chakracore 1.7.1.0 of chakranode I noticed and interop issue when a unit test in my project failed.

```js
o = {}
o.b = 2
o.a = 1
delete o.b
o.b = 2
Object.keys(o) // produces [ 'b', 'a' ] while v8 produces ['a', 'b']
```
The example uses `Object.keys` but `for-in` and friends will produce a similar result.