Remove AsyncError with Expando.

tests/standalone/io/socket_test.dart

Index: tests/standalone/io/socket_test.dart
diff --git a/tests/standalone/io/socket_test.dart b/tests/standalone/io/socket_test.dart
index a405c05ad63c1de259d5cd958d6442ef1b1aa423..1385b67893d9e179215a688137bed3567f1fcbf9 100644
--- a/tests/standalone/io/socket_test.dart
+++ b/tests/standalone/io/socket_test.dart
@@ -34,16 +34,16 @@ void testInvalidBind() {
   // Bind to a unknown DNS name.
   ServerSocket.bind("ko.faar.__hest__")
       .then((_) { Expect.fail("Failure expected"); } )
-      .catchError((e) {
-        Expect.isTrue(e.error is SocketIOException);
+      .catchError((error) {
+        Expect.isTrue(error is SocketIOException);
         port.toSendPort().send(1);
       });
 
   // Bind to an unavaliable IP-address.
   ServerSocket.bind("8.8.8.8")
       .then((_) { Expect.fail("Failure expected"); } )
-      .catchError((e) {
-        Expect.isTrue(e.error is SocketIOException);
+      .catchError((error) {
+        Expect.isTrue(error is SocketIOException);
         port.toSendPort().send(1);
       });
 
@@ -59,9 +59,9 @@ void testInvalidBind() {
               Expect.equals(s.port, t.port);
               port.toSendPort().send(1);
             })
-            .catchError((e) {
+            .catchError((error) {
               Expect.notEquals('windows', Platform.operatingSystem);
-              Expect.isTrue(e.error is SocketIOException);
+              Expect.isTrue(error is SocketIOException);
               port.toSendPort().send(1);
             });
       });