Comment render caching breaks comments with patches attached

Now that comments are render cached, the comments aren't updated when a patch is picked up by the bot.
This prevents finding the simpletest results, or using tools like https://github.com/Lullabot/drupal_qa_notifier to subscribe to the patch results.

On top of that, when the patches pass or fail, the comments are not updated.
The standard red/green of patches is very helpful, and it can be confusing if a patch looks stuck.

Can we possibly split this out somehow, or not cache comments that upload patches?