Cynthia Littleton Business EditorUniversal Television chief Pearlena Igbokwe has been elevated to head of TV content for NBCUniversal as part of the broader shakeup of NBCU’s senior executive ranks. Bonnie Hammer, the NBCU veteran who had been overseeing all TV production, segues into the NBCU vice chairman role that was hastily vacated last month by Ron Meyer.The shuffle in NBCUniversal’s content group comes at the same time the company is poised to bring in longtime Warner Bros.