The title of this Great Performances special baffles me. It leaves off the first name, Gustavo, of music director Dudamel, and shortens the Los Angeles Philharmonic to “LA Phil.” (To me, LA Phil was a guy I used to see twice a year on press tour.) And it doesn’t even mention the host, Natalie Portman, or the special musical guest, violinist Itzhtak Perlman. But I guess John Williams, composer of so many scores for Steven Spielberg movies, pretty much sells himself, even in titu