You can joke that it was the huge online reaction to the series finale of Pretty Little Liars on cable last night but Nielsen numbers for Tuesday's primetime ratings are nowhere to be found so fat today. "We don't have any hard information except that there is a delay," said one frustrated network executive this morning of the lack of ratings among adults 18-49 and viewership numbers. Though it might be annoying to the Big 4 not knowing how America's Got Talent, The Bachel…