Reland "Trigger exception debug event for promises at the throw site."

test/mjsunit/es6/debug-promises-caught-uncaught.js

Index: test/mjsunit/es6/debug-promises-caught-uncaught.js
diff --git a/test/mjsunit/es6/debug-promises-caught-uncaught.js b/test/mjsunit/es6/debug-promises-caught-uncaught.js
index b7f6d48196e436d77fc0e1f68fa7de19e26ff8c7..9620d31bddda93f0d4644e5b3c2bfc8925aca484 100644
--- a/test/mjsunit/es6/debug-promises-caught-uncaught.js
+++ b/test/mjsunit/es6/debug-promises-caught-uncaught.js
@@ -6,8 +6,7 @@
 
 // Test debug events when we only listen to uncaught exceptions and
 // there is a catch handler for the exception thrown in a Promise.
-// Expectation:
-//  - no debug event is triggered.
+// We expect no debug event to be triggered.
 
 Debug = debug.Debug;
 
@@ -28,7 +27,6 @@ q.catch(
 function listener(event, exec_state, event_data, data) {
   try {
     assertTrue(event != Debug.DebugEvent.Exception);
-    assertTrue(event != Debug.DebugEvent.PendingExceptionInPromise);
   } catch (e) {
     // Signal a failure with exit code 1.  This is necessary since the
     // debugger swallows exceptions and we expect the chained function