By Caroline Valetkevitch NEW YORK (Reuters) – Global stock indexes fell and the dollar was slightly lower against other major currencies on Wednesday ahead of what is expected to be another aggressive interest rate hike from the U.S. Federal Reserve later in the day. U.S. Treasury yields were little changed. The U.S. central bank is expected to announce a fourth three-quarters of a percentage point increase, part of its effort to bring down inflation. The policy statement from the bank’s Federal Open Market Committee (FOMC) is due at 2 p.m. EDT (1800 GMT). The Fed has raised its benchmark over…