Don't use SO_OPENTYPE in Windows debugger. It was probably deprecated
at some point, and the same feature can be achieved with WSASocket.

The documentation reads (about SO_OPENTYPE):

> Once set, affects whether subsequent sockets that are created will
> be non-overlapped. The possible values for this option are
> SO_SYNCHRONOUS_ALERT and SO_SYNCHRONOUS_NONALERT. This option should
> not be used. Instead use the WSASocket function and leave the
> WSA_FLAG_OVERLAPPED bit in the dwFlags parameter turned off.

https://docs.microsoft.com/en-us/windows/win32/winsock/sol-socket-socket-options

This allows to merge Windows-specific code and to remove all the
sockopt related code. Keeping the _open_osfhandle error is not
necessary.

No change entry needed