This makes the tests easier to copy and relocate to other test numbers without having to update content. Closes #6738
When CURL_SOCKET_BAD is returned in the callback, it should be treated as an error (CURLE_COULDNT_CONNECT) if no other socket is subsequently created when trying to connect to a server. Bug: http://curl.haxx.se/mail/lib-2015-06/0047.html