Disney’s new “Tarzan” musical is “one of the most expensive shows ever mounted on Broadway, with a budget rumored to be between $15 million and $20 million. It is also one of the riskiest, even for Disney, a company which has had an excellent Broadway track record, with three hits in three tries. Most shows open out of town, where problems can be identified and fixed far from prying eyes. But “Tarzan,” based on the hit 1999 animated film and the classic Edgar Rice Burroughs novel that inspired it, will land on Broadway cold.”