Bug 1522339 - Part 1: Do not assert the result of the delete operation when tracking unhandled promise rejections. r=jorendorff

Differential Revision: https://phabricator.services.mozilla.com/D17781

--HG--
extra : moz-landing-system : lando

js/src/shell/js.cpp

@@ -1093,7 +1093,8 @@ static bool TrackUnhandledRejections(JSContext* cx, JS::HandleObject promise,
                               &deleted)) {
         return false;
       }
-      MOZ_ASSERT(deleted);
+      // We can't MOZ_ASSERT(deleted) here, because it's possible we failed to
+      // add the promise in the first place, due to OOM.
       break;
   }