Remove AsyncError with Expando.

tests/standalone/io/http_server_early_client_close_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";
 import "dart:io";
 import "dart:isolate";
 
 void sendData(List<int> data, int port) {
@@ skipping 21 matching lines @@
     bool calledOnError = false;
     ReceivePort port = new ReceivePort();
     server.listen(
         (request) {
           Expect.isTrue(expectRequest);
           Expect.isFalse(calledOnError);
           Expect.isFalse(calledOnRequest, "onRequest called multiple times");
           calledOnRequest = true;
           request.listen(
               (_) {},
-              onError: (e) {
+              onError: (error) {
                 Expect.isFalse(calledOnError);
-                Expect.equals(exception, e.error.message);
+                Expect.equals(exception, error.message);
                 calledOnError = true;
                 port.close();
                 c.complete(null);
               });
         },
-        onError: (e) {
+        onError: (error) {
           Expect.isFalse(calledOnError);
-          Expect.equals(exception, e.error.message);
+          Expect.equals(exception, error.message);
           Expect.equals(expectRequest, calledOnRequest);
           calledOnError = true;
           port.close();
           c.complete(null);
         });
 
     List<int> d;
     if (data is List<int>) d = data;
     if (data is String) d = data.codeUnits;
     if (d == null) Expect.fail("Invalid data");
@@ skipping 94 matching lines @@
           socket.done.catchError((_) {});
         });
   });
 }
 
 void main() {
   testEarlyClose1();
   testEarlyClose2();
   testEarlyClose3();
 }