Windows stream server closing deadlock
On windows, the first test succeeds, but the second one hangs:
```nim
  asyncTest "Works":
    let server = createStreamServer(initTAddress("127.0.0.1:0"))
    let acceptFut = server.accept()
    
    await acceptFut.cancelAndWait()
    server.close()
    await server.join()

  asyncTest "Hangs":
    let server = createStreamServer(initTAddress("127.0.0.1:0"))
    let acceptFut = server.accept()
    
    server.close()
    discard await allFinished(@[acceptFut.cancelAndWait(), server.join()])
```

On other platform they both work fine.