As suggested in rust-lang#88564. This adds a `try_clone()` to `OwnedFd` by
refactoring the code out of the existing `File`/`Socket` code.

`WSADuplicateSocketW` returns 0 on success, which differs from
handle-oriented functions which return 0 on error. Use `sys::net::cvt`
to handle its return value, which handles the socket convention of
returning 0 on success, rather than `sys::cvt`, which handles the
handle-oriented convention of returning 0 on failure.