Fix PromiseHasRejectHandler.

test/mjsunit/es6/debug-promises/reject-caught-by-default-reject-handler.js

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Flags: --expose-debug-as debug --allow-natives-syntax
 
 // Test debug events when we only listen to uncaught exceptions and
-// there is a catch handler for the to-be-rejected Promise.
-// We expect an Exception debug event with a promise to be triggered.
+// there is only a default reject handler for the to-be-rejected Promise.
+// We expect two Exception debug events:
+//  - when the first Promise is rejected and only has default reject handlers.
+//  - when the default reject handler passes the rejection on.
 
 Debug = debug.Debug;
 
 var expected_events = 2;
 var log = [];
 
 var resolve, reject;
 var p0 = new Promise(function(res, rej) { resolve = res; reject = rej; });
 var p1 = p0.then(function() {
   log.push("p0.then");
@@ skipping 55 matching lines @@
     }
   }
 
   // Run testDone through the Object.observe processing loop.
   var dummy = {};
   Object.observe(dummy, checkResult);
   dummy.dummy = dummy;
 }
 
 testDone(0);