MIAMI — Shohei Ohtani sparked a ninth-inning rally with a leadoff double, and Munetaka Murakami hit a walk-off, two-run double to lift Japan over Mexico 6-5 Monday night and into the World Baseball Classic final. Yu Darvish is set to start when Japan faces the defending champion United States in Tuesday night’s championship game — Japan has won the tournament twice, Team USA has done it once. Merrill Kelly is likely to start for the U.S. side. Ohtani went 2 for 4. The Los Angeles Angels star scored in the seventh when Masataka Yoshida hit a tying, three-run homer off…