Remove old InputStream and OutputStream classes from dart:io.

tests/standalone/io/file_test.dart

 // Copyright (c) 2012, 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.
 //
 // Dart test program for testing file I/O.
 
 import 'dart:async';
 import 'dart:io';
 import 'dart:isolate';
 
@@ skipping 58 matching lines @@
         });
   }
 
   // Test for file read and write functionality.
   static void testReadWriteStream() {
     asyncTestStarted();
 
     // Read a file.
     String inFilename = getFilename("tests/vm/data/fixed_length_file");
     File file;
-    InputStream input;
     int bytesRead;
 
     var file1 = new File(inFilename);
     List<int> buffer = new List<int>();
     file1.openRead().listen(
       (d) {
         buffer.addAll(d);
       },
       onDone: () {
         Expect.equals(42, buffer.length);
@@ skipping 1132 matching lines @@
       testDirectorySync();
       testWriteStringUtf8();
       testWriteStringUtf8Sync();
     });
   }
 }
 
 main() {
   FileTest.testMain();
 }