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

pkg/compiler/lib/src/parser/node_listener.dart

 // Copyright (c) 2015, 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 dart2js.parser.node_listener;
 
 import '../common.dart';
 import '../elements/elements.dart' show CompilationUnitElement;
 import 'package:front_end/src/fasta/parser/parser.dart'
     show FormalParameterType;
@@ skipping 284 matching lines @@
       constructor = new Send(classReference, name);
     }
     pushNode(constructor);
   }
 
   @override
   void endRedirectingFactoryBody(Token beginToken, Token endToken) {
     pushNode(new RedirectingFactoryBody(beginToken, endToken, popNode()));
   }
 
+  void endExpressionFunctionBody(Token arrowToken, Token endToken) {
+    endReturnStatement(true, arrowToken, endToken);
+  }
+
   @override
   void endReturnStatement(
       bool hasExpression, Token beginToken, Token endToken) {
     Expression expression = hasExpression ? popNode() : null;
     pushNode(new Return(beginToken, endToken, expression));
   }
 
   @override
   void endYieldStatement(Token yieldToken, Token starToken, Token endToken) {
     Expression expression = popNode();
@@ skipping 690 matching lines @@
     }
     lastErrorWasNativeFunctionBody = false;
   }
 
   void internalError({Token token, Node node}) {
     // TODO(ahe): This should call reporter.internalError.
     Spannable spannable = (token == null) ? node : token;
     throw new SpannableAssertionFailure(spannable, 'Internal error in parser.');
   }
 }