BOSTON — Klay Thompson’s shot hasn’t been up to his championship standard in the first two games of the NBA Finals. But he just might have a modern solution to the issue of a shooting slump. Over six straight playoff runs, Thompson has developed a funk-breaking trick that he hopes will work for Game 3: The Warriors guard pulls up YouTube, searches for his own highlight clips, and learns a thing or two from his past self. “That’s the beauty of playing in today’s age,” Thompson said. “You can go on YouTube and look up all your great moments.” It’s become routine for Thompson amid some of his bad…