Anita Corsaut is Steve McQueen's girl friend in "The Blob." Who is she you are Shirley asking yourself. Opie's school marm, Ms. Helen Crump, on "The Andy Griffith Show." TCM ran the movie last nite after "20 Million Miles to Earth." And our genial host, Robert Osborne, related how this was Steve's first movie and how the flick was the sleeper of 1958. And whatever happened to Frances Bavier, eh? v.c.