By Promit Mukherjee OTTAWA (Reuters) -The Bank of Canada is almost certain to reduce its key policy rate to 2.25% on Wednesday, with President Donald Trump's latest threats of higher tariffs reinforcing expectations that a rate cut would be needed to help spur demand and support growth. Money markets show a more than 90% chance of a 25 basis point rate cut, up from an 80% chance last week, after Trump cut off trade talks and said he would impose more tariffs on Canada out of anger over an anti-tariff TV ...