‘The Supremes at Earl’s All-You-Can-Eat’ Review: Trio Sticks Together

It would be difficult to spoil one of most rousing scenes in “The Supremes at Earl’s All-You-Can-Eat,” if only because it figures mightily into the movie’s trailer. One gets the sense that director Tina Mabry doesn’t intend to spoil the fun either so much as emphasize the feisty fealty she practiced in adapting Edward Kelsey Moore’s 2013 novel, which centers on lifelong friends…