Revert "Remove Expect from core library."

tests/language/function_type_parameter_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.
 
-import "package:expect/expect.dart";
-
 // Test to check that we can parse closure type formal parameters with
 // default value.
 
 class A {
   final f;
   A(int this.f());
 
   static Function func;
 
   static SetFunc([String fmt(int i) = null]) {
     func = fmt;
   }
 
 }
 
 main() {
   Expect.equals(null, A.func);
   A.SetFunc((i) => "$i");
   Expect.equals(false, null == A.func);
   Expect.equals("1234", A.func(1230 + 4));
   A.SetFunc();
   Expect.equals(null, A.func);
 
   Expect.equals(42, new A(() => 42).f());
 }