False positive on mutual recursion involving a type alias

This produces an error but (I think) shouldn't:
```
from typing import List

class A(object):
    b: 'B'  # E: Invalid type "recurse.B"

B = List[A]
```
It works fine if I make `B` a class, even a class inheriting from `A`. I encountered this in https://github.com/JelleZijlstra/typeshed_client/blob/master/typeshed_client/parser.py#L30 (A is NameInfo and B is NameDict).