Change core lib, dart2js, and more for new optional parameters syntax

tests/standalone/io/stream_pipe_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.
 //
 // VMOptions=
 // VMOptions=--short_socket_read
 // VMOptions=--short_socket_write
 // VMOptions=--short_socket_read --short_socket_write
 
 #import("dart:io");
 #import("dart:isolate");
 #source("testing_server.dart");
 
 // Helper method to be able to run the test from the runtime
 // directory, or the top directory.
 String getDataFilename(String path) =>
     new File(path).existsSync() ? path : '../$path';
 
 
 bool compareFileContent(String fileName1,
                         String fileName2,
-                        [int file1Offset = 0,
-                         int file2Offset = 0,
-                         int count]) {
+                        {int file1Offset: 0,
+                         int file2Offset: 0,
+                         int count}) {
   var file1 = new File(fileName1).openSync();
   var file2 = new File(fileName2).openSync();
   var length1 = file1.lengthSync();
   var length2 = file2.lengthSync();
   if (file1Offset == 0 && file2Offset == 0 && count == null) {
     if (length1 != length2) {
       file1.closeSync();
       file2.closeSync();
       return false;
     }
@@ skipping 250 matching lines @@
   srcStream.pipe(dstStream, close: false);
 }
 
 
 main() {
   testFileToFilePipe1();
   testFileToFilePipe2();
   testFileToFilePipe3();
   PipeServerGame echoServerGame = new PipeServerGame.start();
 }