Wrong type when creating an instance from a type which inherits from a generic class

The following code is fine:

```
function create<T>(ctor: { new (): T }) {
    return new ctor();
}

class A { }
class B<T> extends A { }
let b = create(B); // b: B<any> --> OK
```

But if A is generic, the type is not correct.

```
class A<T> { }
class B<T> extends A<T> { }
let b = create(B); // b: A<any> --> Should be B<any>
```

Sorry if this has already been reported.
