Fix PromiseHasRejectHandler.

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

Index: test/mjsunit/es6/debug-promises/reject-caught-by-default-reject-handler.js
diff --git a/test/mjsunit/es6/debug-promises/reject-caught-by-default-reject-handler.js b/test/mjsunit/es6/debug-promises/reject-caught-by-default-reject-handler.js
index 7760b0eb4cfbb3ffad0f07dac3c13e7918204328..63151df016c9bdaec3e43c145a3ba10f4433b110 100644
--- a/test/mjsunit/es6/debug-promises/reject-caught-by-default-reject-handler.js
+++ b/test/mjsunit/es6/debug-promises/reject-caught-by-default-reject-handler.js
@@ -5,8 +5,10 @@
 // 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;