Fix utility function in smoke, add tests for it.

pkg/smoke/lib/src/common.dart

 // Copyright (c) 2014, 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.
 
 /// Some common utilities used by other libraries in this package.
 library smoke.src.common;
 
 import 'package:smoke/smoke.dart' as smoke show isSubclassOf;
 
 /// Returns [input] adjusted to be within [min] and [max] length. Truncating it
@@ skipping 66 matching lines @@
   if (f is _Func0) return 0;
   return -1;
 }
 
 /// Shallow comparison of two lists.
 bool compareLists(List a, List b, {bool unordered: false}) {
   if (a == null && b != null) return false;
   if (a != null && b == null) return false;
   if (a.length != b.length) return false;
   if (unordered) {
-    var bSet = new Set()..addAll(b);
-    for (int i = 0; i < a.length; i++) {
-      if (!bSet.contains(a[i])) return false;
+    var countMap = {};
+    for (var x in b) {
+      var count = countMap[x];
+      if (count == null) count = 0;
+      countMap[x] = count + 1;
     }
+    for (var x in a) {
+      var count = countMap[x];
+      if (count == null) return false;
+      if (count == 1) {
+        countMap.remove(x);
+      } else {
+        countMap[x] = count - 1;
+      }
+    }
+    return countMap.isEmpty;
   } else {
     for (int i = 0; i < a.length; i++) {
       if (a[i] != b[i]) return false;
     }
   }
   return true;
 }
 
 /// Shallow comparison of two maps.
 bool compareMaps(Map a, Map b) {
   if (a == null && b != null) return false;
   if (a != null && b == null) return false;
   if (a.length != b.length) return false;
   for (var k in a.keys) {
     if (!b.containsKey(k) || a[k] != b[k]) return false;
   }
   return true;
 }