They’re definitely back. The Will & Grace gang wasted no time at the Tribeca TV Festival before jumping into the present and taking a swipe at Donald Trump — just as quickly and easily as they seem to have fallen back into old their roles. David Kohan, asked how he’d react if Trump called him “a son of a bitch” — that’s how the president referred to Colin Kaepernick last night — the W&G co-creator said without a beat, “I guess I would rather be a son of a bitch than the…