Remove deprecated Expect from the libraries.

tests/language/argument_definition6_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.
 
 // Regression test for
 // https://code.google.com/p/dart/issues/detail?id=9090.
 // Parameters used to be passed in the wrong order in a constructor in the
 // presence of parameter checks.
 
+import 'package:expect/expect.dart';
 
 class A {
   A(expect1, expect2, value1, value2, {layers, serviceUrl}) {
     Expect.equals(expect1, ?layers);
     Expect.equals(expect2, ?serviceUrl);
     Expect.equals(value1, layers);
     Expect.equals(value2, serviceUrl);
   }
 }
 
 main() {
   new A(false, false, null, null);
   new A(true, false, 42, null, layers: 42);
   new A(false, true, null, 43, serviceUrl: 43);
   new A(true, true, 42, 43, layers: 42, serviceUrl: 43);
   new A(true, true, 42, 43, serviceUrl: 43, layers: 42);
 }