dart2js cps: Set result of 'await' to dynamic instead of empty.

pkg/compiler/lib/src/cps_ir/type_propagation.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 dart2js.cps_ir.type_propagation;
 
 import 'optimizers.dart';
 
 import '../closure.dart' show
     ClosureClassElement, Identifiers;
 import '../common/names.dart' show
@@ skipping 2493 matching lines @@
     setValue(node, nonConstant(typeSystem.elementTypeOfIndexable(input.type)));
   }
 
   @override
   void visitSetIndex(SetIndex node) {
     setValue(node, nonConstant());
   }
 
   @override
   void visitAwait(Await node) {
-    Continuation continuation = node.continuation.definition;
-    setReachable(continuation);
+    setResult(node, nonConstant());
   }
 
   @override
   void visitRefinement(Refinement node) {
     AbstractValue value = getValue(node.value.definition);
     if (value.isNothing ||
         typeSystem.areDisjoint(value.type, node.refineType)) {
       setValue(node, nothing);
     } else if (value.isConstant) {
       setValue(node, value);
@@ skipping 115 matching lines @@
   processLetPrim(LetPrim node) {
     node.primitive.type = null;
     values[node.primitive] = null;
   }
 
   processLetMutable(LetMutable node) {
     node.variable.type = null;
     values[node.variable] = null;
   }
 }