Update dart:io tests to use asyncStart/asyncEnd

tests/standalone/io/socket_ipv6_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 'dart:io';
-import 'dart:isolate';
+
+import "package:async_helper/async_helper.dart";
 
 const ANY = InternetAddressType.ANY;
 
 void testIPv6toIPv6() {
+  asyncStart();
   InternetAddress.lookup("::0", type: ANY).then((serverAddr) {
     InternetAddress.lookup("::1", type: ANY).then((clientAddr) {
         ServerSocket.bind(serverAddr.first, 0).then((server) {
         server.listen((socket) {
           socket.destroy();
           server.close();
+          asyncEnd();
         });
         Socket.connect(clientAddr.first, server.port).then((socket) {
           socket.destroy();
         });
       });
     });
   });
 }
 
 void testIPv4toIPv6() {
+  asyncStart();
   InternetAddress.lookup("::0", type: ANY).then((serverAddr) {
       ServerSocket.bind(serverAddr.first, 0).then((server) {
       server.listen((socket) {
         socket.destroy();
         server.close();
+        asyncEnd();
       });
       Socket.connect("127.0.0.1", server.port).then((socket) {
         socket.destroy();
       });
     });
   });
 }
 
 void testIPv6toIPv4() {
+  asyncStart();
   InternetAddress.lookup("::1", type: ANY).then((clientAddr) {
       ServerSocket.bind("127.0.0.1", 0).then((server) {
       server.listen((socket) {
         throw "Unexpected socket";
       });
       Socket.connect(clientAddr.first, server.port).catchError((e) {
         server.close();
+        asyncEnd();
       });
     });
   });
 }
 
 void testIPv4toIPv4() {
+  asyncStart();
   ServerSocket.bind("127.0.0.1", 0).then((server) {
     server.listen((socket) {
       socket.destroy();
       server.close();
+      asyncEnd();
     });
     Socket.connect("127.0.0.1", server.port).then((socket) {
       socket.destroy();
     });
   });
 }
 
 void testIPv6Lookup() {
-  var port = new ReceivePort();
+  asyncStart();
   InternetAddress.lookup("::0", type: ANY).then((list) {
     if (list.length < 0) throw "no address";
     for (var entry in list) {
       if (entry.type != InternetAddressType.IP_V6) {
         throw "Wrong IP type";
       }
     }
-    port.close();
+    asyncEnd();
   });
 }
 
 void testIPv4Lookup() {
-  var port = new ReceivePort();
+  asyncStart();
   InternetAddress.lookup("127.0.0.1").then((list) {
     if (list.length < 0) throw "no addresse";
     for (var entry in list) {
       if (entry.type != InternetAddressType.IP_V4) {
         throw "Wrong IP type";
       }
     }
-    port.close();
+    asyncEnd();
   });
 }
 
 void testIPv4toIPv6_IPV6Only() {
+  asyncStart();
   InternetAddress.lookup("::0", type: ANY)
       .then((serverAddr) {
         ServerSocket.bind(serverAddr.first, 0, v6Only: true)
             .then((server) {
               server.listen((socket) {
                 throw "Unexpcted socket";
               });
               Socket.connect("127.0.0.1", server.port).catchError((error) {
                 server.close();
+                asyncEnd();
               });
             });
       });
 }
 
 void main() {
   testIPv6toIPv6();
   testIPv4toIPv6();
   testIPv6toIPv4();
   testIPv4toIPv4();
   testIPv6Lookup();
   testIPv4Lookup();
 
   testIPv4toIPv6_IPV6Only();
 }