multi: alter transfer timeout ordering

- Check whether a connection has succeded before checking whether it's
  timed out.

  This means if we've connected quickly, but subsequently been
  descheduled, we allow the connection to succeed. Note, if we timeout,
  but between checking the timeout, and connecting to the server the
  connection succeeds, we will allow it to go ahead. This is viewed as
  an acceptable trade off.

- Add additional failf logging around failed connection attempts to
  propogate the cause up to the caller.

Co-Authored-by: Martin Howarth
Closes #7178

lib/url.c

@@ -3374,9 +3374,12 @@ static CURLcode resolve_server(struct Curl_easy *data,
       if(rc == CURLRESOLV_PENDING)
         *async = TRUE;
 
-      else if(rc == CURLRESOLV_TIMEDOUT)
+      else if(rc == CURLRESOLV_TIMEDOUT) {
+        failf(data, "Failed to resolve host '%s' with timeout after %ld ms",
+              connhost->dispname,
+              Curl_timediff(Curl_now(), data->progress.t_startsingle));
         result = CURLE_OPERATION_TIMEDOUT;
-
+      }
       else if(!hostaddr) {
         failf(data, "Could not resolve host: %s", connhost->dispname);
         result = CURLE_COULDNT_RESOLVE_HOST;