Update dart:io tests to use asyncStart/asyncEnd

tests/standalone/io/socket_upgrade_to_secure_test.dart

Index: tests/standalone/io/socket_upgrade_to_secure_test.dart
diff --git a/tests/standalone/io/socket_upgrade_to_secure_test.dart b/tests/standalone/io/socket_upgrade_to_secure_test.dart
index ba2bed03f15040716aea67d6368eb92755bcbd28..efbc1434256bd156ea1f03d99c110fa975709428 100644
--- a/tests/standalone/io/socket_upgrade_to_secure_test.dart
+++ b/tests/standalone/io/socket_upgrade_to_secure_test.dart
@@ -7,11 +7,12 @@
 // VMOptions=--short_socket_write
 // VMOptions=--short_socket_read --short_socket_write
 
-import "package:expect/expect.dart";
-import "package:path/path.dart";
 import "dart:async";
 import "dart:io";
-import "dart:isolate";
+
+import "package:async_helper/async_helper.dart";
+import "package:expect/expect.dart";
+import "package:path/path.dart";
 
 const HOST_NAME = "localhost";
 const CERTIFICATE = "localhost_cert";
@@ -40,7 +41,7 @@ const CERTIFICATE = "localhost_cert";
 void test(bool hostnameInConnect,
           bool handshakeBeforeSecure,
           [bool postponeSecure = false]) {
-  ReceivePort port = new ReceivePort();
+  asyncStart();
 
   const messageSize = 1000;
   const handshakeMessageSize = 100;
@@ -204,7 +205,7 @@ void test(bool hostnameInConnect,
     });
 
     connectClient(server.port).then(runClient).then((socket) {
-      port.close();
+      asyncEnd();
     });
   }