wip: accept
Add Network.Socket.Windows.accept, including UPDATE_ACCEPT_CONTEXT
N.S.W.accept: discard the local address received
N.S.W.accept: set SO_UPDATE_CONNECT_CONTEXT on connect
lab/connect.hs: follow new accept, and call getSocketName and getPeerName after accept and connect

The getSocketName and/or getPeerName calls fail if the SO_UPDATE_ACCEPT_CONTEXT
and SO_UPDATE_CONNECT_CONTEXT steps aren't performed.