Add List.reversed to give a reverse fixed-length view of a list.

runtime/lib/growable_array.dart

Index: runtime/lib/growable_array.dart
diff --git a/runtime/lib/growable_array.dart b/runtime/lib/growable_array.dart
index 6498f20dd8282d36701ea0eb4a15da5fb191b713..c9925fbb959362a70af5d05e84d403e61fb7407e 100644
--- a/runtime/lib/growable_array.dart
+++ b/runtime/lib/growable_array.dart
@@ -291,6 +291,8 @@ class _GrowableObjectArray<T> implements List<T> {
     this.length = 0;
   }
 
+  List<T> get reversed => new ReversedList<T>(this, 0, length);
+
   void sort([int compare(T a, T b)]) {
     if (compare == null) compare = Comparable.compare;
     _Sort.sort(this, compare);