By Davide Barbuscia and David Randall NEW YORK (Reuters) – A series of surprise actions by some of the world’s largest central banks fretting about runaway inflation has left bond investors battered. Now, a growing chorus of investors is calling on policymakers to move fast to end the uncertainty. Until central banks are able to bring down inflation, some investors said, markets will not have any certainty about rates. Their best way forward may be to get to neutral interest rates — the level at which monetary policy is neither stimulating nor restricting the economy — as fast as they can, t…