pkg/test: Resolve a number of analyzer warnings

lib/src/util/io.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';
 import 'dart:mirrors';
 
 import 'package:path/path.dart' as p;
 import 'package:pub_semver/pub_semver.dart';
 
 import '../backend/operating_system.dart';
 import '../runner/application_exception.dart';
 import '../util/stream_queue.dart';
 import '../utils.dart';
@@ skipping 15 matching lines @@
 /// Returns the current operating system.
 final OperatingSystem currentOS = (() {
   var name = Platform.operatingSystem;
   var os = OperatingSystem.findByIoName(name);
   if (os != null) return os;
 
   throw new UnsupportedError('Unsupported operating system "$name".');
 })();
 
 /// A queue of lines of standard input.
-final stdinLines = new StreamQueue(
-    UTF8.decoder.fuse(const LineSplitter()).bind(stdin));
+final stdinLines = new StreamQueue(lineSplitter.bind(stdin));
 
 /// Whether this is being run as a subprocess in the test package's own tests.
 bool inTestTests = Platform.environment["_DART_TEST_TESTING"] == "true";
 
 /// The root directory below which to nest temporary directories created by the
 /// test runner.
 ///
 /// This is configurable so that the test code can validate that the runner
 /// cleans up after itself fully.
 final _tempDir = Platform.environment.containsKey("_UNITTEST_TEMP_DIR")
@@ skipping 121 matching lines @@
 ///
 /// This has a built-in race condition: another process may bind this port at
 /// any time after this call has returned. If at all possible, callers should
 /// use [getUnusedPort] instead.
 Future<int> getUnsafeUnusedPort() async {
   var socket = await RawServerSocket.bind(InternetAddress.LOOPBACK_IP_V4, 0);
   var port = socket.port;
   await socket.close();
   return port;
 }