Cleanup deferred test fixes.

tests/compiler/dart2js_extra/deferred/deferred_constant_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";
 import 'dart:async';
 
 @lazy import 'deferred_class_library.dart';
 
 const lazy = const DeferredLibrary('deferred_class_library');
 
-class Expect {
-  static void isTrue(x) => Expect.equals(true, x);
-  static void isFalse(x) => Expect.equals(false, x);
-
-  static void equals(expected, actual) {
-    if (expected != actual) {
-      throw "Not equal. Expected: $expected. Got: $actual";
-    }
-  }
-
-  static void throws(fun, [test]) {
-    try {
-      fun();
-    } catch (e) {
-      if (!test(e)) throw "doesn't satisfy exception test";
-      return;
-    }
-    throw "didn't throw";
-  }
-
-  static void isNull(x) => expect.equals(null, x);
-}
-
 main() {
   var x;
   // TODO(ahe): What are the semantics of this:
   // x = const MyClass();
   Expect.isNull(x);
   int counter = 0;
   lazy.load().then((bool didLoad) {
     Expect.isTrue(didLoad);
     Expect.equals(1, ++counter);
     print('deferred_class_library was loaded');
     x = const MyClass();
     Expect.equals(42, x.foo(87));
   });
   Expect.equals(0, counter);
   Expect.isNull(x);
   lazy.load().then((bool didLoad) {
     Expect.isFalse(didLoad);
     Expect.equals(2, ++counter);
     print('deferred_class_library was loaded');
     x = const MyClass();
     Expect.equals(42, x.foo(87));
   });
   Expect.equals(0, counter);
   Expect.isNull(x);
   // TODO(ahe): What are the semantics of this:
   // x = const MyClass();
   Expect.isNull(x);
 }