The struggling Yakult Swallows put on a power display Saturday, hitting three home runs in a 6-4 come-from-behind victory over the Central League pennant-contending DeNA BayStars. Trailing 3-0 in the fourth at Tokyo’s historic Jingu Stadium, Munetaka Murakami hit a solo homer, his second in two games, to start the fightback for the last-place Swallows. Hideki Nagaoka’s two-run double made it a 4-3 game in the fifth before Jose Osuna homered for the second straight game to tie it in the sixth. Osuna then provided the final blow with a two-run homer in the eighth. Swallows starter Cy Sneed surre…