Fix debug-promises tests.

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

Index: test/mjsunit/es6/debug-promises/throw-uncaught-uncaught.js
diff --git a/test/mjsunit/es6/debug-promises/throw-uncaught-uncaught.js b/test/mjsunit/es6/debug-promises/throw-uncaught-uncaught.js
index 45e7e0db849a198008bb000a37b2e3037f57ddc7..69aa8ebbd248c2e6fd01770aca7b47126526ce53 100644
--- a/test/mjsunit/es6/debug-promises/throw-uncaught-uncaught.js
+++ b/test/mjsunit/es6/debug-promises/throw-uncaught-uncaught.js
@@ -32,7 +32,7 @@ function listener(event, exec_state, event_data, data) {
       assertTrue(expected_events >= 0);
       assertEquals("uncaught", event_data.exception().message);
       assertTrue(event_data.promise() instanceof Promise);
-      assertEquals(q, event_data.promise());
+      assertSame(q, 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);