Chu’s colorful spectacle (★★★ out of four; rated PG; in theaters Friday), adapted from the popular Broadway musical (based on the Gregory Maguire book) and a revelatory prequel to “The Wizard of Oz.” The song-filled character study of the Wicked Witch of the West’s early years ekes out great performances from Cynthia Erivo and Ariana Grande that’ll wow musical theater kids and old-school “Oz” fans alike.