Incorrect inspection of Set iterator for set.entries()

* **Version**: 10, 11, master
* **Platform**: Linux
* **Subsystem**: util

```js
var set = new Set([1, 2])
console.log(set.entries())
```

In Node 6 and 8, it outputs:

```
SetIterator { [ 1, 1 ], [ 2, 2 ] }
```

In Node 10, 11 and master:

```
[Set Iterator] { 1, 2 }
```