Do not emit semicolons for await expressions in ToSourceVisitor

pkg/analyzer/test/generated/ast_test.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.
 
 library engine.ast_test;
 
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/java_core.dart';
 import 'package:analyzer/src/generated/java_engine.dart' show Predicate;
 import 'package:analyzer/src/generated/java_engine.dart';
@@ skipping 1679 matching lines @@
 
   void test_visitAssignmentExpression() {
     _assertSource(
         "a = b",
         AstFactory.assignmentExpression(AstFactory.identifier3("a"),
             TokenType.EQ, AstFactory.identifier3("b")));
   }
 
   void test_visitAwaitExpression() {
     _assertSource(
-        "await e;", AstFactory.awaitExpression(AstFactory.identifier3("e")));
+        "await e", AstFactory.awaitExpression(AstFactory.identifier3("e")));
   }
 
   void test_visitBinaryExpression() {
     _assertSource(
         "a + b",
         AstFactory.binaryExpression(AstFactory.identifier3("a"), TokenType.PLUS,
             AstFactory.identifier3("b")));
   }
 
   void test_visitBlock_empty() {
@@ skipping 2183 matching lines @@
   static const List<WrapperKind> values = const [
     PREFIXED_LEFT,
     PREFIXED_RIGHT,
     PROPERTY_LEFT,
     PROPERTY_RIGHT,
     NONE
   ];
 
   const WrapperKind(String name, int ordinal) : super(name, ordinal);
 }