LONDON — In a day of intrigue and betrayal, predictions about the next prime minister of Britain were overturned on Thursday as the presumed favorite, Boris Johnson, said he would not run after his ally in the Brexit campaign, Michael Gove, suddenly announced his candidacy.Mr. Gove had once ruled himself out for the job. His U-turn Thursday wrecked Mr. Johnson’s prospects and enhanced those of Theresa May, the home secretary, who had backed the Remain campaign but with little enthusiasm.(nytimes.com)…[+]