Revert "Remove Expect from core library."

tests/language/fannkuch_test.dart

 // Copyright (c) 2011, 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.
 // The Great Computer Language Shootout
 // http://shootout.alioth.debian.org/
 // Ported from JavaScript contributed by Isaac Gouy.
 // Description: Repeatedly acccess a tiny integer-sequence.
 
-import "package:expect/expect.dart";
-
 class FannkuchTest {
   static fannkuch(n) {
     var p = new List(n), q = new List(n), s = new List(n);
     var sign = 1, maxflips = 0, sum = 0, m = n - 1;
     for (var i = 0; i < n; i++) { p[i] = i; q[i] = i; s[i] = i; }
     do {
       // Copy and flip.
       var q0 = p[0];  // Cache 0th element.
       if (q0 != 0) {
         for (var i = 1; i < n; i++) q[i] = p[i];  // Work on a copy.
@@ skipping 41 matching lines @@
     var n = 6;
     var pf = fannkuch(n);
     Expect.equals(49, pf[0]);
     Expect.equals(10, pf[1]);
     print("${pf[0]}\nPfannkuchen($n) = ${pf[1]}");
   }
 }
 main() {
   FannkuchTest.testMain();
 }