Fix to special case Dispose method to be treated as non-action

#1294
@rynowak @yishaigalatzer 
Discussed offline, there's a problem using `DeclaredType` in cases like this:

```
    public class C
    {
        public void Dispose()
        {
            throw new NotImplementedException();
        }
    }

    public class D : C, IDisposable
    {
    }
```

So, we do need the extra `TypeInfo` parameter.