Daniel D'Addario Chief TV CriticThe set of the new Broadway production of “American Buffalo” at Circle in the Square is choked with the unwanted artifacts of recent history. The show’s two acts take place in a junk shop glutted with relics, one whose barest gestures toward organization are just begging to be undone; the place is already sliding into disorder, so why not finish the job?It’s fitting in more ways than this production may anticipate.