Fix debug-promises tests.

test/mjsunit/es6/debug-promises/reject-uncaught-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
 
 // 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.
 
@@ skipping 20 matching lines @@
 })
 
 
 function listener(event, exec_state, event_data, data) {
   try {
     if (event == Debug.DebugEvent.Exception) {
       expected_events--;
       assertTrue(expected_events >= 0);
       assertEquals("uncaught reject p", event_data.exception().message);
       assertTrue(event_data.promise() instanceof Promise);
-      assertEquals(p, event_data.promise());
+      assertSame(p, event_data.promise());
       assertTrue(event_data.uncaught());
       // Assert that the debug event is triggered at the throw site.
       assertTrue(exec_state.frame(0).sourceLineText().indexOf("// event") > 0);
     }
   } catch (e) {
     %AbortJS(e + "\n" + e.stack);
   }
 }
 
 Debug.setBreakOnUncaughtException();
@@ skipping 15 matching lines @@
     }
   }
 
   // Run testDone through the Object.observe processing loop.
   var dummy = {};
   Object.observe(dummy, checkResult);
   dummy.dummy = dummy;
 }
 
 testDone(0);