http: refactor and reduce duplication

vlib/net/ftp/ftp_test.v

@@ -2,16 +2,11 @@ module main
 
 import net.ftp
 
-fn test_ftp_client() {
-	make_client_connection()
-	assert true
-}
-
 // NB: this function makes network calls to external servers,
 // that is why it is not a very good idea to run it in CI.
 // If you want to run it manually, use `v -d network vlib/net/ftp/ftp_test.v`
-[if network]
-fn make_client_connection() {
+fn test_ftp_client() {
+//	$if !network ? { return }
 	mut ftp := ftp.new()
 	defer {
 		ftp.close()