[cleanup] Remove an obsolete TODO

Bug: v8:9183
Change-Id: I1e47de782f0422369096b382427565d5816b99b9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1591614Reviewed-by: Dan Elphick <delphick@chromium.org>
Commit-Queue: Dan Elphick <delphick@chromium.org>
Auto-Submit: Maciej Goszczycki <goszczycki@google.com>
Cr-Commit-Position: refs/heads/master@{#61155}

src/snapshot/serializer.cc

@@ -145,7 +145,6 @@ bool Serializer::SerializeHotObject(HeapObject obj) {
     obj->ShortPrint();
     PrintF("\n");
   }
-  // TODO(ishell): remove kHotObjectWithSkip
   sink_.Put(kHotObject + index, "HotObject");
   return true;
 }