Jon Stewart on Monday night hit both President Joe Biden and former President Donald Trump on “The Daily Show,” lamenting that this year’s presidential election features a pair of nominees so past their primes that each has accused the other of having “soup … where there should be brain.” In his opening monologue, Stewart laid into Biden over a video — since debunked as misleading — that purported to show Biden wandering away during a G7 summit event in Italy late last week. “For President Biden it is his habit of seemingly staring at what can only be considered ghosts or out-of-frame paratr…