AT THE MOVIES, The Nutty Professor, starring Eddie Murphy, debuts at No. 1 with a gross of $25.4 million. ON TV, amid the summer rerun season, original installments of 20/20, PrimeTime Live, and Dateline NBC occupy four of the top five spots in the Nielsen ratings. IN MUSIC, Metallica remains a force to be reckoned with as Load tops the Billboard album chart for the second week. MEANWHILE… Buxom blond actress Gail O’Grady is NYPD Blue-in-the-face as irreconcilable differences lead her to file for divorce from her manager-husband of only 10 months.