BEIJING, May 30 (Reuters) - A private jet used by Tesla Inc (TSLA.O) CEO Elon Musk has arrived in Beijing, according to a Reuters witness. Musk is expected to meet senior Chinese officials and visit Tesla's Shanghai plant, sources have said, in what would be his first trip to China in three years. Tesla did not immediately respond to a request for comment on whether Musk had arrived in China. It was not clear who Musk would meet in China's government and what issues they would discuss. State media had not reported on Musk's visit as of Tuesday afternoon. China's...