[analyzer] fix NodeReplacer for AwaitExpression

pkg/analyzer/lib/src/generated/ast.dart

 // Copyright (c) 2014, 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.
 
 // This code was auto-generated, is not intended to be edited, and is subject to
 // significant change. Please see the README file for more information.
 
 library engine.ast;
 
 import 'dart:collection';
@@ skipping 12448 matching lines @@
       node.rightHandSide = _newNode as Expression;
       return true;
     }
     return visitNode(node);
   }
 
   @override
   bool visitAwaitExpression(AwaitExpression node) {
     if (identical(node.expression, _oldNode)) {
       node.expression = _newNode as Expression;
+      return true;
     }
     return visitNode(node);
   }
 
   @override
   bool visitBinaryExpression(BinaryExpression node) {
     if (identical(node.leftOperand, _oldNode)) {
       node.leftOperand = _newNode as Expression;
       return true;
     } else if (identical(node.rightOperand, _oldNode)) {
@@ skipping 7578 matching lines @@
   }
 
   @override
   accept(AstVisitor visitor) => visitor.visitYieldStatement(this);
 
   @override
   void visitChildren(AstVisitor visitor) {
     _safelyVisitChild(_expression, visitor);
   }
 }