PARIS — Don’t freak out just yet, but maybe start packing emergency supplies. Brussels’ fear of a founding member of the European Union swinging to the far right was abruptly reactivated this week as France’s snowballing political crisis gathered more momentum, leading one of French President Emmanuel Macron’s historic allies  to join the chorus  of opponents calling on him to step down. The French president is under extraordinary pressure after his prime minister’s latest attempt at forming a