Even for a show as harrowing as Hulu’s “The Handmaid’s Tale,” the fourth season of the series, based on the cautionary dystopian book by Margaret Atwood, is surprisingly bleak. Granted, a show dealing with an apocalyptically totalitarian society, known as Gilead, that subjects women, known as “Handmaids,” to child-bearing slavery and servitude, isn’t much of a joyride. However, in the series’ fourth season, the protagonist and central handmaiden, June Osborne’s (Elisabeth Moss) personal demons, threaten to undermine and engulf her.