He took his shot — and hit nothing but net. A longtime street musician scored his dream gig with the Knicks last week when two Madison Square Garden execs happened upon his drumming performance outside the World’s Most Famous Arena. “What are the odds of you just walking past while I’m here trying to bust my ass in the cold trying to pay my rent?” Cornelio Joseph told the dazzled execs. “Hey, let me know if there’s any opportunity for entertainment at the Garden,” he told them. Longtime busker Cornelio Joseph has been pounding the pavement — and his homemade snare drums — for years before catching his big break playing for the Knicks at MSG. Fabio Garcia “I took my shot,” he recalled to The Post. Days later, they texted him to perform at Game 2 of the Eastern Conference semifinals, where the Knicks were taking on the Philadelphia 76ers. “ I was freaking out,” he said. “For the Knicks to find me, this changed my life,” he said after performing in front of 20,000 rabid fans Wednesday night.…