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

tests/corelib/collection_length_test.dart

 // Copyright (c) 2013, 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.
 
 library map_test;
 import 'dart:collection';
 
 // Test that length/isEmpty opertions are constant time on
 // maps, strings and collections.
 
@@ skipping 15 matching lines @@
 
 void testMap(Map map, int n) {
   for (int i = 0; i < n; i++) {
     map[i] = i;
   }
   testLength(map, n);
   testLength(map.keys, n);
   testLength(map.values, n);
 }
 
-void testCollection(Collection collection, n) {
+void testCollection(var collection, n) {
   for (int i = 0; i < n; i++) {
     collection.add(i);
   }
   testLength(collection, n);
 }
 
 void testList(List list, n) {
   // Works even if list is fixed-length.
   for (int i = 0; i < n; i++) {
     list[i] = i;
@@ skipping 20 matching lines @@
   testMap(new LinkedHashMap(), N);
   testMap(new SplayTreeMap(), N);
   testCollection(new HashSet(), N);
   testCollection(new LinkedHashSet(), N);
   testCollection(new ListQueue(), N);
   testCollection(new DoubleLinkedQueue(), N);
   testList(new List()..length = N, N);
   testList(new List(N), N);
   testString(N);
 }