By Rae Wee SINGAPORE (Reuters) -Global shares slipped on Wednesday and gold pulled back sharply from a blistering rally, as stretched valuations came under scrutiny and investors booked profits. Geopolitics loomed large. A planned summit between U.S. President Donald Trump and Russian President Vladimir Putin was put on hold and ambiguity lingered over a potential meeting between Trump and Chinese President Xi Jinping. Despite Washington and Beijing striking a more conciliatory tone in recent times, Tru ...