Fix 'collection' tests and co19 dartc/dart2js status files.

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 and maps.
  */
 
 library collection_to_string;
 
@@ skipping 189 matching lines @@
 /**
  * Populates the given empty collection with elements, emitting the string
  * representation of the collection to stringRep.  The beingMade parameter is
  * a list of collections currently under construction, i.e., candidates for
  * recursive references.
  *
  * If exact is true, the elements of the returned collections will not be,
  * and will not contain a collection with ill-defined iteration order
  * (i.e., a HashSet or HashMap).
  */
-Collection populateRandomCollection(int size, bool exact,
-    StringBuffer stringRep, List beingMade, Collection coll) {
+populateRandomCollection(int size, bool exact,
+    StringBuffer stringRep, List beingMade, var coll) {
   beingMade.add(coll);
   stringRep.write(coll is List ? '[' : '{');
 
   for (int i = 0; i < size; i++) {
     if (i != 0) stringRep.write(', ');
     coll.add(randomElement(random(size), exact, stringRep, beingMade));
   }
 
   stringRep.write(coll is List ? ']' : '}');
   beingMade.removeLast();
@@ skipping 76 matching lines @@
   return rand.nextBool();
 }
 
 /** Returns the alphabetized characters in a string. */
 String alphagram(String s) {
   // Calling [toList] to convert unmodifiable list to normal list.
   List<int> chars = s.codeUnits.toList();
   chars.sort((int a, int b) => a - b);
   return new String.fromCharCodes(chars);
 }