Revert of Disable non-standard Promise functions in staging

test/mjsunit/es6/debug-promises/reject-caught-late.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 --promise-extra
+// Flags: --expose-debug-as debug --allow-natives-syntax
 
 // Test debug events when we only listen to uncaught exceptions, the Promise
 // is rejected, and a catch handler is installed right before the rejection.
 // We expect no debug event to be triggered.
 
 Debug = debug.Debug;
 
 var p = new Promise(function(resolve, reject) {
   resolve();
 });
 
 var q = p.chain(
   function() {
     q.catch(function(e) {
       assertEquals("caught", e.message);
     });
     return Promise.reject(Error("caught"));
   });
 
 function listener(event, exec_state, event_data, data) {
   try {
     assertTrue(event != Debug.DebugEvent.Exception);
   } catch (e) {
     %AbortJS(e + "\n" + e.stack);
   }
 }
 
 Debug.setBreakOnUncaughtException();
 Debug.setListener(listener);