Remove deprecated Expect from the libraries.

tests/language/constructor_initializer_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";
+
 class A {
   var _x, _y;
   A(x, [y = 10]): _x = x++, _y = y++ {
     // Check that value of modified constructor parameters
     // is remembered in the constructor body.
     Expect.equals(x, _x + 1);
     Expect.equals(y, _y + 1);
     Expect.isFalse(?y);
   }
 }
@@ skipping 13 matching lines @@
 main() {
   var o = new B(3, 5);
   Expect.equals(3, o._a);
   Expect.equals(6, o._b);
   Expect.equals(9, o._x);
   Expect.equals(10, o._y);
   o = new A(3);
   Expect.equals(3, o._x);
   Expect.equals(10, o._y);
 }