Don't use external servers in the tests

tests/standalone/io/https_client_exception_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 "dart:uri";
+
+void testBadHostName() {
+  HttpClient client = new HttpClient();
+  ReceivePort port = new ReceivePort();
+  client.getUrl(Uri.parse("https://some.bad.host.name.7654321/"))
+      .then((HttpClientRequest request) {
+        Expect.fail("Should not open a request on bad hostname");
+      })
+      .catchError((error) {
+        port.close();  // Should throw an error on bad hostname.
+      });
+}
+
+void InitializeSSL() {
+  SecureSocket.initialize();
+}
+
+void main() {
+  testBadHostName();
+  Expect.throws(InitializeSSL);
+}