Remove deprecated Expect from the libraries.

tests/standalone/io/link_test.dart

 // Copyright (c) 2013, 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.
 
+import "package:expect/expect.dart";
 import "dart:async";
 import "dart:io";
 import "dart:isolate";
 
 // Test the dart:io Link class.
 
 testCreateSync() {
   Path base = new Path(new Directory('').createTempSync().path);
   String link = base.append('link').toNativePath();
   String target = base.append('target').toNativePath();
@@ skipping 118 matching lines @@
   }
   Future.wait(futures).then((_) {
     baseDir.deleteSync(recursive: true);
   });
 }
 
 
 main() {
   testCreateSync();
 }