Spelling fixes e to i.

runtime/observatory/tests/service/tcp_socket_closing_service_test.dart

 // Copyright (c) 2015, 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:convert';
 import 'dart:io' as io;
 import 'package:observatory/service_io.dart';
 import 'package:unittest/unittest.dart';
 import 'test_helper.dart';
 
 /// Test that we correctly remove sockets that have been closed from the list
-/// of open sockets. We explictly leave one socket open.
+/// of open sockets. We explicitly leave one socket open.
 
 Future setup() async {
   var serverSocket = await io.ServerSocket.bind('127.0.0.1', 0);
   serverSocket.listen((s) {
     s.drain();
     s.close();
   });
   var socket = await io.Socket.connect("127.0.0.1", serverSocket.port);
   socket.write("foobar");
   socket.write("foobar");
@@ skipping 41 matching lines @@
     expect(server['lastRead'], equals(0));
     expect(server['totalRead'], equals(0));
     expect(server['lastWrite'], equals(0));
     expect(server['totalWritten'], equals(0));
     expect(server['writeCount'], equals(0));
     expect(server['readCount'], equals(0));
   },
 ];
 
 main(args) async => runIsolateTests(args, tests, testeeBefore: setup);