Use official named pipe support in Tokio

[abbec]

Named pipe support has been merged in tokio . Scrap use of our own fork and use the official one instead. See https://github.com/tokio-rs/tokio/blob/master/examples/named-pipe.rs and https://docs.rs/tokio/1.12.0/tokio/net/windows/named_pipe/struct.NamedPipeServer.html.