super in object literal causes error

The following code should log:

```
original
new
```

as it does in ES6. Instead in TypeScript 1.6.2 it causes an error:

`'super' can only be referenced in a derived class.`

Here's the code:

```
var obj = {
    __proto__: {
        method() {
            console.log('original');
        }
    },
    method() {
        super.method();
        console.log('new');
    }
};

obj.method();
```
