Several well-known Las Vegas shows are quietly closing their doors, including some big names and fan favorites. No show is safe.  And in recent months, the Strip has seen a wave of cancellations as historic runs have come to an end. And if you’ve been waiting to see one of these productions, you might already be too late. But, you still have a few weeks to catch Mad Apple, as Cirque du Soleil is shutting down this popular Strip show following its 4-year run. Mad Apple combines acrobatics, live music, and stand-up comedy, but its final performance will be September…