Revert "Remove Expect from core library."

tests/compiler/dart2js_extra/this_redirecting_constructor_test.dart

Index: tests/compiler/dart2js_extra/this_redirecting_constructor_test.dart
diff --git a/tests/compiler/dart2js_extra/this_redirecting_constructor_test.dart b/tests/compiler/dart2js_extra/this_redirecting_constructor_test.dart
index 068d62feaf1a2684a803ce594f2178bb7d58e5bb..6962716375f02f073a73bb02f6663cd8ea4714ca 100644
--- a/tests/compiler/dart2js_extra/this_redirecting_constructor_test.dart
+++ b/tests/compiler/dart2js_extra/this_redirecting_constructor_test.dart
@@ -2,8 +2,6 @@
 // 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";
-
 // Confirm that redirecting named constructors are properly resolved.
 //
 // Note that this test may become invalid due to http://dartbug.com/5940.
@@ -18,4 +16,4 @@ class C {
 main() {
   var c = new C.redirecting();
   Expect.equals(c.x, 2);
-}
+}