TOKYO—Maddie Musselman held her phone out, and the U.S. women’s water polo team gathered for a picture on the top step of the podium. It was a familiar scene. The dynasty is alive and well. Musselman scored three times, Ashleigh Johnson made 11 saves and the United States won its third consecutive gold medal on Saturday, routing Spain 14–5 in the final at the Tokyo Olympics. “We’re having fun out there, and I think you could see that today,” Musselman said. “Everyone brought their best when their best was needed.” Aria Fischer, Kaleigh Gilchrist, and Alys Williams had two goals apiece as the United States improved to 134–4 since it won gold at the 2016 Rio de Janeiro Games. It broke its own records for most goals and the biggest margin in the final. Maggie Steffens and Melissa Seidemann became the first women to win three gold medals in women’s …