“Parasite” has officially infected Hollywood’s award season. Bong Joon Ho’s Korean class satire became the first foreign language film to take top honors from the Screen Actors Guild on Sunday, setting itself up as a legitimate best picture contender to the front-runner “1917” at next month’s Academy Awards. The best ensemble win for “Parasite” came over the starry epics “Once Upon a Time … in Hollywood” and “The Irishman.” It was a surprise but only to a degree.