Make List.skip, List.take and List.reversed return Iterables, not Lists.

runtime/lib/array.dart

Index: runtime/lib/array.dart
diff --git a/runtime/lib/array.dart b/runtime/lib/array.dart
index 3ce453bba5e3625287e521949cf1ca9908b2a019..0f02eb4c01c30ff062241f0ecba9190cf985d55f 100644
--- a/runtime/lib/array.dart
+++ b/runtime/lib/array.dart
@@ -164,7 +164,7 @@ class _ObjectArray<E> implements List<E> {
     return this.length == 0;
   }
 
-  List<E> get reversed => new ReversedListView<E>(this, 0, null);
+  Iterable<E> get reversed => new ReversedListIterable<E>(this);
 
   void sort([int compare(E a, E b)]) {
     IterableMixinWorkaround.sortList(this, compare);
@@ -402,7 +402,7 @@ class _ImmutableArray<E> implements List<E> {
     return this.length == 0;
   }
 
-  List<E> get reversed => new ReversedListView<E>(this, 0, null);
+  Iterable<E> get reversed => new ReversedListIterable<E>(this);
 
   void sort([int compare(E a, E b)]) {
     throw new UnsupportedError(