Several bugfixes in dart:io's handing of sockets

dart/tests/standalone/io/server_socket_reference_issue21383_and_issue21384_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:async';
+import 'dart:io';
+
+import 'package:async_helper/async_helper.dart';
+
+
+testBothListen() {
+  asyncStart();
+  ServerSocket.bind('127.0.0.1', 0).then((mainServer) {
+    mainServer.reference.create().then((refServer) {
+      refServer.listen((_) {});
+      mainServer.listen((_) {});
+      Timer.run(() {
+        mainServer.close();
+        refServer.close();
+        asyncEnd();
+      });
+    });
+  });
+}
+
+testRefServerListen() {
+  asyncStart();
+  ServerSocket.bind('127.0.0.1', 0).then((mainServer) {
+    mainServer.reference.create().then((refServer) {
+      refServer.listen((_) {});
+      Timer.run(() {
+        mainServer.close();
+        refServer.close();
+        asyncEnd();
+      });
+    });
+  });
+}
+
+testMainServerListen() {
+  asyncStart();
+  ServerSocket.bind('127.0.0.1', 0).then((mainServer) {
+    mainServer.reference.create().then((refServer) {
+      mainServer.listen((_) {});
+      Timer.run(() {
+        mainServer.close();
+        refServer.close();
+        asyncEnd();
+      });
+    });
+  });
+}
+
+testNoneListen() {
+  asyncStart();
+  ServerSocket.bind('127.0.0.1', 0).then((mainServer) {
+    mainServer.reference.create().then((refServer) {
+      Timer.run(() {
+        mainServer.close();
+        refServer.close();
+        asyncEnd();
+      });
+    });
+  });
+}
+
+main() {
+  testNoneListen();
+  testMainServerListen();
+  testRefServerListen();
+  testBothListen();
+}
+