By Tobias Carroll If you happen to be a pet owner, what’s your go-to pet food brand? There’s a growing trend in ads for dog and cat food to emphasize the same sort of high-quality ingredients that you might find in high-end grocery items. And while that makes sense on one level — premium ingredients may well be healthier for your dog than the alternative — it’s also worth pointing out that, if left to their own devices, dogs will eat some genuinely foul things. All of which brings us to this weekend’s Saturday Night Live, which found John Mulaney returning to the show for his fifth stint as ho…