Get rid of all the library tags.

lib/src/util/io.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-library test.util.io;
-
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 import 'dart:mirrors';
 
 import 'package:path/path.dart' as p;
 import 'package:pub_semver/pub_semver.dart';
 
 import '../backend/operating_system.dart';
 import '../runner/application_exception.dart';
@@ skipping 158 matching lines @@
 ///
 /// This has a built-in race condition: another process may bind this port at
 /// any time after this call has returned. If at all possible, callers should
 /// use [getUnusedPort] instead.
 Future<int> getUnsafeUnusedPort() async {
   var socket = await RawServerSocket.bind(InternetAddress.LOOPBACK_IP_V4, 0);
   var port = socket.port;
   await socket.close();
   return port;
 }