The Philadelphia Orchestra’s summer season at the Saratoga Performing Arts Center opens on Wednesday with three weeks of fabulous music, two movies and several artists making their debuts.While the opening concert will celebrate the season with fan favorites like Tchaikovsky’s “1812 Overture” and his Symphony No. 5, the surprise is to hear concertmaster David Kim playing Tchaikovsky’s Violin Concerto for the first time for SPAC audiences.“This is my 24th season with the orchestra and I’ve done this concerto several times,” he said. “It’s my favorite piece to play and the one most requested. But as we age, different issues or…