Fix test for parsing 'await'.

pkg/analyzer/test/generated/parser_fasta_test.dart

 // Copyright (c) 2017, 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.
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart' as analyzer;
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/error/error.dart';
 import 'package:analyzer/src/generated/parser.dart' as analyzer;
 import 'package:analyzer/src/generated/utilities_dart.dart';
@@ skipping 334 matching lines @@
   @override
   @failingTest
   void
       test_parseAssignableExpression_identifier_args_dot_typeParameterComments() {
     super
         .test_parseAssignableExpression_identifier_args_dot_typeParameterComments();
   }
 
   @override
   @failingTest
-  void test_parseAwaitExpression() {
-    super.test_parseAwaitExpression();
-  }
-
-  @override
-  @failingTest
   void test_parseCascadeSection_ia_typeArgumentComments() {
     super.test_parseCascadeSection_ia_typeArgumentComments();
   }
 
   @override
   @failingTest
   void test_parseCascadeSection_ia_typeArguments() {
     super.test_parseCascadeSection_ia_typeArguments();
   }
 
@@ skipping 369 matching lines @@
       if (code.isEmpty) {
         return _parseExpression('foo');
       }
       return _parseExpression('(foo)$code');
     }
     return _parseExpression('foo$code');
   }
 
   @override
   AwaitExpression parseAwaitExpression(String code) {
-    return _parseExpression(code);
+    var function = _parseExpression('() async => $code') as FunctionExpression;
+    return (function.body as ExpressionFunctionBody).expression;
   }
 
   @override
   Expression parseBitwiseAndExpression(String code) {
     return _parseExpression(code);
   }
 
   @override
   Expression parseBitwiseOrExpression(String code) {
     return _parseExpression(code);
@@ skipping 751 matching lines @@
   void test_parseTypeAlias_genericFunction_typeParameters_voidReturnType() {
     super.test_parseTypeAlias_genericFunction_typeParameters_voidReturnType();
   }
 
   @override
   @failingTest
   void test_parseTypeAlias_genericFunction_voidReturnType() {
     super.test_parseTypeAlias_genericFunction_voidReturnType();
   }
 }