Remove Expect from core library.

tests/language/methods_as_constants_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.
 
+import "package:expect/expect.dart";
+
 topLevelMethod() => 't';
 
 const topLevelFieldForTopLevelMethod = topLevelMethod;
 const topLevelFieldForStaticMethod = A.staticMethod;
 
 class A {
   final Function closure;
   const A(this.closure);
   const A.defaultTopLevel([this.closure = topLevelMethod]);
   const A.defaultStatic([this.closure = staticMethod]);
@@ skipping 16 matching lines @@
   Expect.equals('s', (new A.defaultStatic2()).run());
   Expect.equals('t', topLevelFieldForTopLevelMethod());
   Expect.equals('s', topLevelFieldForStaticMethod());
   Expect.equals('t', A.staticFieldForTopLevelMethod());
   Expect.equals('s', A.staticFieldForStaticMethod());
 
   var map = const {'t': topLevelMethod, 's': A.staticMethod };
   Expect.equals('t', map['t']());
   Expect.equals('s', map['s']());
 }