Remove addLast from List.

runtime/lib/array.dart

Index: runtime/lib/array.dart
diff --git a/runtime/lib/array.dart b/runtime/lib/array.dart
index 1a8977eb6c4c48161109bebc02ae5100a77173b7..696bfcc5adca81966fdcd329fb5204903ac05ec5 100644
--- a/runtime/lib/array.dart
+++ b/runtime/lib/array.dart
@@ -194,10 +194,6 @@ class _ObjectArray<E> implements List<E> {
         "Cannot add to a non-extendable array");
   }
 
-  void addLast(E element) {
-    add(element);
-  }
-
   void addAll(Iterable<E> iterable) {
     throw new UnsupportedError(
         "Cannot add to a non-extendable array");
@@ -446,10 +442,6 @@ class _ImmutableArray<E> implements List<E> {
         "Cannot add to an immutable array");
   }
 
-  void addLast(E element) {
-    add(element);
-  }
-
   void addAll(Iterable<E> elements) {
     throw new UnsupportedError(
         "Cannot add to an immutable array");