WASHINGTON — Alexander Butterfield, the White House aide who inadvertently hastened Richard Nixon’s resignation over the Watergate scandal when he revealed that the president had bugged the Oval Office and Cabinet Room and routinely recorded his conversations, has died. He was 99. His death was confirmed by his wife, Kim, and John Dean, who served as White House counsel to Nixon during the Watergate scandal and went on to, along with Butterfield, help expose the wrongdoing . “He had the heavy