Change new List(n) to return fixed length list.

tests/corelib/collection_removes_test.dart

 // Copyright (c) 2011, 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.
 
 testRemove(Collection base) {
   int length = base.length;
   for (int i = 0; i < length; i++) {
     Expect.isFalse(base.isEmpty);
     base.remove(base.first);
   }
@@ skipping 68 matching lines @@
   }
 }
 
 void main() {
   var collections = [
     [], [1], [2], [1, 2], [1, 2, 3, 4, 5, 6, 7, 8, 9, 10],
     [1, 3, 5, 7, 9], [2, 4, 6, 8, 10]
   ];
   for (var base in collections) {
     for (var delta in collections) {
-      testRemove(base.toList());
+      testRemove(base.toList(growable: true));
       testRemove(base.toSet());
 
       var deltaSet = delta.toSet();
-      testRemoveAll(base.toList(), delta);
-      testRemoveAll(base.toList(), deltaSet);
-      testRetainAll(base.toList(), delta);
-      testRetainAll(base.toList(), deltaSet);
-      testRemoveMatching(base.toList(), deltaSet.contains);
-      testRetainMatching(base.toList(), (e) => !deltaSet.contains(e));
+      testRemoveAll(base.toList(growable: true), delta);
+      testRemoveAll(base.toList(growable: true), deltaSet);
+      testRetainAll(base.toList(growable: true), delta);
+      testRetainAll(base.toList(growable: true), deltaSet);
+      testRemoveMatching(base.toList(growable: true), deltaSet.contains);
+      testRetainMatching(base.toList(growable: true),
+                         (e) => !deltaSet.contains(e));
 
       testRemoveAll(base.toSet(), delta);
       testRemoveAll(base.toSet(), deltaSet);
       testRetainAll(base.toSet(), delta);
       testRetainAll(base.toSet(), deltaSet);
       testRemoveMatching(base.toSet(), deltaSet.contains);
       testRetainMatching(base.toSet(), (e) => !deltaSet.contains(e));
     }
   }
 }