Do not emit InvalidStatement in sanitize_for_vm pass

pkg/kernel/lib/transformations/sanitize_for_vm.dart

 // Copyright (c) 2016, 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.
 library kernel.transformations.fixvm;
 
 import '../ast.dart';
 
 /// Ensures that classes all have either a constructor or a procedure.
 ///
 /// VM-specific constraints that don't fit in anywhere else can be put here.
 class SanitizeForVM {
   void transform(Program program) {
     for (var library in program.libraries) {
       for (var class_ in library.classes) {
         if (class_.constructors.isEmpty && class_.procedures.isEmpty) {
           class_.addMember(new Constructor(
-              new FunctionNode(new InvalidStatement()),
+              new FunctionNode(new EmptyStatement()),
               name: new Name('')));
         }
       }
     }
   }
 }