Model 'await for' as an explicit node in tree and fix its handling.

pkg/compiler/lib/src/ssa/nodes.dart

 // Copyright (c) 2012, 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.
 
 part of ssa;
 
 abstract class HVisitor<R> {
   R visitAdd(HAdd node);
   R visitAwait(HAwait node);
   R visitBitAnd(HBitAnd node);
@@ skipping 2896 matching lines @@
   bool accept(HStatementInformationVisitor visitor) =>
     visitor.visitLabeledBlockInfo(this);
 }
 
 class LoopTypeVisitor extends ast.Visitor {
   const LoopTypeVisitor();
   int visitNode(ast.Node node) => HLoopBlockInformation.NOT_A_LOOP;
   int visitWhile(ast.While node) => HLoopBlockInformation.WHILE_LOOP;
   int visitFor(ast.For node) => HLoopBlockInformation.FOR_LOOP;
   int visitDoWhile(ast.DoWhile node) => HLoopBlockInformation.DO_WHILE_LOOP;
-  int visitForIn(ast.ForIn node) => HLoopBlockInformation.FOR_IN_LOOP;
+  int visitAsyncForIn(ast.AsyncForIn node) => HLoopBlockInformation.FOR_IN_LOOP;
+  int visitSyncForIn(ast.SyncForIn node) => HLoopBlockInformation.FOR_IN_LOOP;
   int visitSwitchStatement(ast.SwitchStatement node) =>
       HLoopBlockInformation.SWITCH_CONTINUE_LOOP;
 }
 
 class HLoopBlockInformation implements HStatementInformation {
   static const int WHILE_LOOP = 0;
   static const int FOR_LOOP = 1;
   static const int DO_WHILE_LOOP = 2;
   static const int FOR_IN_LOOP = 3;
   static const int SWITCH_CONTINUE_LOOP = 4;
@@ skipping 222 matching lines @@
 class HDynamicType extends HRuntimeType {
   HDynamicType(DynamicType dartType, TypeMask instructionType)
       : super(const <HInstruction>[], dartType, instructionType);
 
   accept(HVisitor visitor) => visitor.visitDynamicType(this);
 
   int typeCode() => HInstruction.DYNAMIC_TYPE_TYPECODE;
 
   bool typeEquals(HInstruction other) => other is HDynamicType;
 }