TREASURIES-U.S. benchmark, long-dated yields hit record lows on global uncertainty

NEW YORK, July 5- Yields on long-term U.S. Treasuries sank to record lows on Tuesday as global investors loaded up on U.S. government debt in hopes it would shield them from threats to the global economy including fallout from Britain's vote to split from the European Union. "This is pessimism on a global scale," said Aaron Kohli, interest rate strategist at BMO...