TWO CATCHY CABLE CONCEITS THIS week involve ne'er-do-wells who somehow get the job done. Cracker is a British miniseries on A&E starring rotund music-hall comic Robbie Coltrane (Nuns on the Run) as a forensic psychologist who is a police consultant and a hive of nasty habits: smoking, drinking, gambling. He is also—as he proves in three stand-alone movies on consecutive Tuesdays at 9 p.m. ET (beginning March 29)—blindingly astute about human behavior. On the Showtime movie Royce (Sun., April 3, 8 p.m. ET), James Belushi (Red Heat) plays an American secret agent tracking a cell of rogue colleagues into Ukraine. With Belushi's invariably callow, cocky manner, it's like watching a frat-house James Bond. Still, Royce rolls.