SALT LAKE CITY — Belief hasn’t wavered in the Vegas Golden Knights ’ locker room heading into a pivotal Game 4, but that’s not stopping coach John Tortorella from making noticeable lineup changes. Chief among them is Tortorella debuting new power-play units ahead of Monday against the Utah Mammoth at Delta Center . Mitch Marner has been bumped to the second unit in favor of defenseman Shea Theodore, and Ivan Barbashev is replacing Tomas Hertl at the net-front spot. “I think we’ve lost the special teams battle the last three games here,” said Tortorella, with his team down 2-1 in the best-of-seven series. “It’s been a big part of where we’re at. We wanted to change something. We wanted to balance it a little bit. We’ll see where it goes.” Tortorella called the power play “too deliberate” after Game 3, where the unit went 0-for-4 in the 4-2 loss . The top unit has been a five-forward look almost all season, primarily because of Marner’s defensive ability and playmaking prowess.…