There’s a terrific tension at the center of Jesse Eisenberg’s directorial debut, “When You Finish Saving The World,” and it seems to do with liberal ideology, identity, projection, and the push and pull fractures parents have with their teenage children and vice versa. Written and directed by Eisenberg and starring Julianne Moore and “Stranger Things” stars Finn Wolfhard, “When You Finish Saving The World” essentially is a comedic family drama about a mother and son who are trying to fill the gaps with how they no longer fit with other people.