Revert "Remove Expect from core library."

tests/language/type_cast_vm_test.dart

 // Copyright (c) 2012, 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.
 // VMOptions=--no_show_internal_names
+//
 // Dart test program testing type casts.
-import "package:expect/expect.dart";
 
 // Test that the initializer expression gets properly skipped.
 bool b = "foo" as double;
 
 class TypeTest {
   static test() {
     int result = 0;
     try {
       var i = "hello" as int;  // Throws a CastError
     } on TypeError catch (error) {
@@ skipping 136 matching lines @@
     Expect.equals(1, testReturn());
     Expect.equals(1, testField());
     Expect.equals(1, testAnyFunction());
   }
 }
 
 
 main() {
   TypeTest.testMain();
 }