What was the best bit during the so-so SNL that host Larry David promised in his opening monologue? The breath-of-fresh-air appearance of Derek Zoolander (Ben Stiller) and Hans (Owen Wilson) during “Weekend Update” to pronounce, fashionwise, on the state of the presidential candidates. OK, so I’m a sucker for malaprops (“couscous” for “caucuses”) and rimshot rejoinders, but after David’s surly predictability too-often reprised, I belly-laughed at the separated-at-birth…