Fix handling of lazy and and or in async functions.

pkg/compiler/lib/src/js/rewrite_async.dart

 // Copyright (c) 2015, 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 rewrite_async;
 
 import "dart:math" show max;
 import 'dart:collection';
 
 import 'package:_internal/compiler/js_lib/shared/async_await_error_codes.dart'
@@ skipping 786 matching lines @@
 
   @override
   js.Expression visitBinary(js.Binary node) {
     if (shouldTransform(node.right) && (node.op == "||" || node.op == "&&")) {
       int thenLabel = newLabel("then");
       int joinLabel = newLabel("join");
       withExpression(node.left, (js.Expression left) {
         js.Statement assignLeft = isResult(left)
             ? new js.Block.empty()
             : js.js.statement('# = #;', [result, left]);
-        if (node.op == "||") {
+        if (node.op == "&&") {
           addStatement(js.js.statement('if (#) {#} else #',
               [left, gotoAndBreak(thenLabel), assignLeft]));
         } else {
-          assert(node.op == "&&");
+          assert(node.op == "||");
           addStatement(js.js.statement('if (#) {#} else #',
               [left, assignLeft, gotoAndBreak(thenLabel)]));
         }
       }, store: true);
       addGoto(joinLabel);
       beginLabel(thenLabel);
       withExpression(node.right, (js.Expression value) {
         if (!isResult(value)) {
           addStatement(js.js.statement('# = #;', [result, value]));
         }
@@ skipping 1702 matching lines @@
     return condition || body;
   }
 
   @override
   bool visitDartYield(js.DartYield node) {
     hasYield = true;
     visit(node.expression);
     return true;
   }
 }