Revert "Remove Expect from core library."

tests/standalone/float_array_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.
 //
 // Dart test program for testing native float arrays.
 
 // Library tag to be able to run in html test framework.
 library FloatArrayTest;
 
-import "package:expect/expect.dart";
 import 'dart:typeddata';
 
 void testCreateFloat32Array() {
   Float32List floatArray;
 
   floatArray = new Float32List(0);
   Expect.equals(0, floatArray.length);
 
   floatArray = new Float32List(10);
   Expect.equals(10, floatArray.length);
@@ skipping 186 matching lines @@
   testBadValues32();
   testBadValues64();
   // Check optimized (inlined) version of []=
   Expect.throws(() {
     storeIt32(a32, 1, 2);
   });
   Expect.throws(() {
     storeIt64(a64, 1, 2);
   });
 }