The United Arab Emirates ramped up deliveries of military supplies to Libyan warlord Khalifa Haftar this year, according to a confidential United Nations report, flouting an arms embargo as the Gulf state tried to salvage the leader’s military campaign and check the influence of regional rival Turkey. The U.A.E.’s military flights surged as Mr. Haftar fought to prevent the collapse of his yearlong attack on Libya’s internationally recognized government in Tripoli, according to a diplomat with access to an unpublished report…