Chris Willman Senior Music Writer and Chief Music CriticThe term “residency” wasn’t always associated with big-bucks Las Vegas bookings designed for pop stars to make a lot of money while staying parked in one place. And in Los Angeles, it’s still not: That’s thanks to Largo, a smallish theater (and formerly an even smaller nightclub) that rotates famous and semi-famous musicians and comedians through its lineup again and again, with the idea that, if you return after a month or four, you’ll usually see a different show.