Revert "Add "last" setter to List."

sdk/lib/html/dart2js/html_dart2js.dart

Index: sdk/lib/html/dart2js/html_dart2js.dart
diff --git a/sdk/lib/html/dart2js/html_dart2js.dart b/sdk/lib/html/dart2js/html_dart2js.dart
index c54b236b69e69b460836e920474e3019dd60f371..3a1e464a3ce902b7ed2fa402ec09a573789d4a18 100644
--- a/sdk/lib/html/dart2js/html_dart2js.dart
+++ b/sdk/lib/html/dart2js/html_dart2js.dart
@@ -33145,11 +33145,7 @@ abstract class ImmutableListMixin<E> implements List<E> {
     return new FixedSizeListIterator<E>(this);
   }
 
-  // From List<E>:
-  void set last(E value) {
-    throw new UnsupportedError("Cannot modify an immutable List.");
-  }
-
+  // From Collection<E>:
   void add(E value) {
     throw new UnsupportedError("Cannot add to immutable List.");
   }
@@ -33158,6 +33154,7 @@ abstract class ImmutableListMixin<E> implements List<E> {
     throw new UnsupportedError("Cannot add to immutable List.");
   }
 
+  // From List<E>:
   void sort([int compare(E a, E b)]) {
     throw new UnsupportedError("Cannot sort immutable List.");
   }