fix nt accept/connect not initializing with SO_UPDATE_*_CONTEXT

[G4Vi]

Fixes calling getpeername, getsockname, getsockopt, setsockopt after accept
and getpeername, getsockname, getsockopt, setsockopt, shutdown after connect.

[jart]

Is there any reason why this is a work in progress? Could you explain more about what exactly is happening here?

[G4Vi]

This change alone is an improvement and can be merged now if you like!

Before __imp_setsockopt(args->listensock, SOL_SOCKET, kNtSoUpdateAcceptContext, &handle, sizeof(handle)) was never (at least observed) being called as I think nonblocking io is always used to make the AcceptEx call. This change makes it always be called after a successful accept.

This was marked WIP to see if anything can be done about noticing that the __imp_setsockopt call fails with WSAENOTSOCK if f->handle was created before forking.

[G4Vi]

Further investigation revealed issues with how sockets are passed to child processes #1174 This is ready for final review, just added test and added link to issue.

[G4Vi]

I just added fixes for the same issue with connect.