This is the next-to-last evening (I’m tired of typing “penultimate”) for “Summer Under the Stars,” and the saluted celebrity, today and tonight, is Italian star Marcello Mastroianni. A lot of his best films are not here, but the one leading off prime time, in particular, certainly is: At 8 p.m. ET, it’s 1963’s 8 ½, a wild satire about European filmmaking in which Mastroianni plays a weary, world-famous film director looking for inspiration, and a