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

tests/corelib/collection_to_string_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.
 
 /**
  * Tests for the toString methods on collections (including maps).
  */
 
 #library('collection_to_string');
 #import('dart:math', prefix: 'Math');
@@ skipping 97 matching lines @@
   }
 }
 
 /**
  * Return a random collection (or Map) of the specified size, placing its
  * string representation into the given string buffer.
  *
  * If exact is true, the returned collections will not be, and will not contain
  * a collection with ill-defined iteration order (i.e., a HashSet or HashMap).
  */
-Object randomCollection(int size, StringBuffer stringRep, [bool exact]) {
+Object randomCollection(int size, StringBuffer stringRep, {bool exact}) {
   return randomCollectionHelper(size, exact, stringRep, []);
 }
 
 /**
  * Return a random collection (or map) of the specified size, placing its
  * string representation into the given string buffer. The beingMade
  * parameter is a list of collections currently under construction, i.e., 
  * candidates for recursive references.
  *
  * If exact is true, the returned collections will not be, and will not contain
@@ skipping 165 matching lines @@
 bool randomBool() {
   return rand.nextBool();
 }
 
 /** Returns the alphabetized characters in a string. */
 String alphagram(String s) {
   List<int> chars = s.charCodes();
   chars.sort((int a, int b) => a - b);
   return new String.fromCharCodes(chars);
 }