Fix parsing [a]sync[*] function body modifiers with Fasta.

pkg/front_end/lib/src/fasta/source/stack_listener.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 fasta.stack_listener;
 
 import 'package:front_end/src/fasta/parser.dart' show ErrorKind, Listener;
 
 import 'package:front_end/src/fasta/parser/identifier_context.dart'
     show IdentifierContext;
@@ skipping 14 matching lines @@
   BreakTarget,
   CascadeReceiver,
   Combinators,
   ConditionalUris,
   ConstructorReferenceContinuationAfterTypeArguments,
   ContinueTarget,
   Expression,
   FieldInitializer,
   FormalParameters,
   FunctionBody,
+  FunctionBodyAsyncToken,
+  FunctionBodyStarToken,
   IdentifierList,
   Initializers,
   Metadata,
   Modifiers,
   ParameterDefaultValue,
   SwitchScope,
   Type,
   TypeArguments,
   TypeList,
   TypeVariable,
@@ skipping 246 matching lines @@
     list.setRange(0, arrayLength, array);
     return list;
   }
 
   void _grow() {
     final List newTable = new List(array.length * 2);
     newTable.setRange(0, array.length, array, 0);
     array = newTable;
   }
 }