Remove the certificate management methods from dart:io

tests/standalone/io/certificate_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.
-
-// This test verifies that a server certificate can be verified by a client
-// that loads the certificate authority certificate it depends on at runtime.
-
-import "package:path/path.dart";
-import "dart:io";
-import "dart:async";
-
-String scriptDir = dirname(new Options().script);
-
-void main() {
-  SecureSocket.initialize(database: join(scriptDir, 'pkcert'),
-                          password: 'dartdart');
-  runServer().then((SecureServerSocket server) {
-    return Process.run(new Options().executable,
-                       ['--checked',
-                        join(scriptDir, 'certificate_test_client.dart'),
-                        server.port.toString(),
-                        join(scriptDir, 'pkcert', 'myauthority.pem')]);
-  }).then((ProcessResult result) {
-    if (result.exitCode != 0 || !result.stdout.contains("SUCCESS")) {
-      print("Client failed with exit code ${result.exitCode}");
-      print("  stdout (expects \"SUCCESS\\n\"):");
-      print(result.stdout);
-      print("  stderr:");
-      print(result.stderr);
-      throw new AssertionError();
-    }
-  });
-}
-
-Future<SecureServerSocket> runServer() =>
-  SecureServerSocket.bind("localhost", 0, "localhost_cert")
-    .then((server) => server..listen(
-        (socket) => socket.pipe(socket).then((_) => server.close())));