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

src/debug-debugger.js

 // Copyright 2012 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.
 
 // Default number of frames to include in the response to backtrace request.
 var kDefaultBacktraceLength = 10;
 
 var Debug = {};
 
 // Regular expression to skip "crud" at the beginning of a source line which is
 // not really code. Currently the regular expression matches whitespace and
 // comments.
 var sourceLineBeginningSkip = /^(?:\s*(?:\/\*.*?\*\/)*)*/;
 
 // Debug events which can occour in the V8 JavaScript engine. These originate
 // from the API include file debug.h.
 Debug.DebugEvent = { Break: 1,
                      Exception: 2,
                      NewFunction: 3,
                      BeforeCompile: 4,
                      AfterCompile: 5,
-                     ScriptCollected: 6 };
+                     ScriptCollected: 6,
+                     PendingExceptionInPromise: 7 };
 
 // Types of exceptions that can be broken upon.
 Debug.ExceptionBreak = { Caught : 0,
                          Uncaught: 1 };
 
 // The different types of steps.
 Debug.StepAction = { StepOut: 0,
                      StepNext: 1,
                      StepIn: 2,
                      StepMin: 3,
@@ skipping 2559 matching lines @@
 
     default:
       json = null;
   }
   return json;
 }
 
 Debug.TestApi = {
   CommandProcessorResolveValue: DebugCommandProcessor.resolveValue_
 };