Joining Republican presidential nominee Donald Trump onstage at a campaign rally in Arizona Friday night, Robert F. Kennedy Jr. tried to emphasize what the two share. “We talked about not the values that separate us, because we don’t agree on everything, but on the values and issues that bind us together,” Kennedy said shortly after suspending his independent presidential bid to throw his support behind Trump. But Kennedy did not mention that he and Trump have in common the same billionaire megadonor, a reclusive heir to a Gilded Age fortune who has pumped over $165 million into the 2024 campa…