Hiding behind owly glasses, Julianne Moore pulls off a perfect Diane Keaton impersonation in “Gloria Bell” (2019). Gloria’s a middle-aged divorcee, living a seemingly full life. Yet there’s an emptiness, as if she’s stuffing life with busyness because there’s no single thing that challenges her. Oh boy, she finds it one night while out disco dancing. Brooding Arnold (John Turturro), who says he, too, is divorced, but suffers from needy millennial daughters. Arnold and Gloria are on and off and on again, as the movie’s momentum goes down the drain, like all those years middle-aged divorcees wish they had back.