In the United States, it is called “lawfare” but for the more agrarian, the term “bulldozer law” might be more appropriate, Martin Hayden submitted to the High Court on Friday morning.  John Magnier, a billionaire who sits at the head of his Coolmore global bloodstock empire, had threatened litigation that would cost millions, drag on for years, and delay the sale of the Barne Estate in Co Tipperary if the deal did not go his way. It was no idle threat, the court was told. The businessman —  who had remarked on his second day in the witness box that…