By Mark Jones Before Manchester United’s famous double late salvo in Barcelona in 1999 they had a dress rehearsal. Four months before that iconic Champions League final win over Bayern Munich which secured the Treble, United scored twice late on to beat Liverpool 2-1 at Old Trafford in the FA Cup fourth round, with Dwight Yorke equalising in the 88th minute and then, sure enough, Ole Gunnar Solskjaer grabbing the winner in stoppage time. It was a sickener for a Liverpool side who had led ever since Michael Owen’s third minute goal, but it exposed the issues facing manager Gerard Houllier, then…