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

lib/compiler/implementation/js/printer.dart

Index: lib/compiler/implementation/js/printer.dart
===================================================================
--- lib/compiler/implementation/js/printer.dart	(revision 13496)
+++ lib/compiler/implementation/js/printer.dart	(working copy)
@@ -72,7 +72,7 @@
   }
 
   visitCommaSeparated(List<Node> nodes, int hasRequiredType,
-                      [bool newInForInit, bool newAtStatementBegin]) {
+                      {bool newInForInit, bool newAtStatementBegin}) {
     for (int i = 0; i < nodes.length; i++) {
       if (i != 0) {
         atStatementBegin = false;
@@ -80,7 +80,8 @@
         spaceOut();
       }
       visitNestedExpression(nodes[i], hasRequiredType,
-                            newInForInit, newAtStatementBegin);
+                            newInForInit: newInForInit,
+                            newAtStatementBegin: newAtStatementBegin);
     }
   }
 
@@ -92,7 +93,7 @@
     visitAll(program.body);
   }
 
-  bool blockBody(Node body, [bool needsSeparation, bool needsNewline]) {
+  bool blockBody(Node body, {bool needsSeparation, bool needsNewline}) {
     if (body is Block) {
       spaceOut();
       blockOut(body, false, needsNewline);
@@ -376,7 +377,7 @@
   }
 
   visitNestedExpression(Expression node, int requiredPrecedence,
-                        [bool newInForInit, bool newAtStatementBegin]) {
+                        {bool newInForInit, bool newAtStatementBegin}) {
     bool needsParentheses =
         // a - (b + c).
         (requiredPrecedence != EXPRESSION &&