Suddenly, and without too much warning, Phil Mickelson is in a major flirtation with history. In ordinary times, his pursuit this weekend of a career grand slam would have been treated as the quixotic dream of the superannuated golfer who had to be granted a special exemption to play in the U.S. Open. But these are not ordinary times and Phil Mickelson is no ordinary golfer. Three weeks ago, he became the oldest major winner in golf, a month shy of his 51st birthday. It was an unlikely win dipped in romance for the player who had spent the last…