Last year’s mop-up man became this year’s Yankees hero

From mop-up to moonwalk. Yes, one year’s time has been very kind to Dellin Betances — and the Yankees. Are you ready for the first Yankees-Red Sox postseason series since 2004? It’s happening, by virtue of the Yankees’ 7-2 defeat of the A’s Wednesday night in the American League wild-card game. Game 1 of the…