That there is nothing novel about the basic premise of “Resident Alien,” a showcase for actor Alan Tudyk premiering Thursday on Syfy, is not a problem. Indeed, in its very familiarity the template — extraterrestrial(s) stranded on and/or infiltrating Earth hides its/their identity — becomes almost a blank slate, allowing as many variations as “Two people with different temperaments live together,” the mulch from which a thousand comedies have bloomed. “Mork & Mindy,” “The Coneheads,” “The Brother From Another Planet,” “Roswell,” the “Roswell” reboot, “The Neighbors,” “Invader Zim” and for that matter Superman are among the many examples to spring from that well.