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

tests/compiler/dart2js/unparser2_test.dart

Index: tests/compiler/dart2js/unparser2_test.dart
===================================================================
--- tests/compiler/dart2js/unparser2_test.dart	(revision 13496)
+++ tests/compiler/dart2js/unparser2_test.dart	(working copy)
@@ -64,7 +64,7 @@
   MessageCollector() {
     messages = [];
   }
-  void cancel([String reason, node, token, instruction, element]) {
+  void cancel(String reason, {node, token, instruction, element}) {
     messages.add(reason);
     throw reason;
   }