Revert "Remove Expect from core library."

tests/language/bailout7_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";
-
 // Test to make sure the do/while loop exit condition is generated.
 
 var global;
 
 class A {
   var array;
 
   initArray() {
     if (global[0] == null) {
       return [2];
@@ skipping 22 matching lines @@
   for (int i = 0; i < 2; i++) {
     Expect.equals(2, new A().bar());
   }
 
   global = new Map();
   global[0] = 2;
   for (int i = 0; i < 2; i++) {
     Expect.equals(2, new A().bar());
   }
 }