Traits disregard constructor types for parent::__construct

### HHVM Version

```
$ hhvm --version
HipHop VM 3.18.0-dev (rel)
Compiler: heads/master-0-g50dd51306377a0ab0cdb4025a889a4d4a067fafb
Repo schema: 289cff02435340d8db866067b16b2c524b599b5e
```

Reproduced in 3.16.0

### Standalone code, or other way to reproduce the problem

```hack
> attribute
```

### Actual result

```
No errors!
```

But fatals when executed.