By Gertrude Chavez-Dreyfuss and Laura Matthews NEW YORK (Reuters) -Bond investors are buying longer-term maturities up to 10-year debt and ramping up bets on a steeper yield curve, anticipating that the Federal Reserve will cut interest rates this week after a nine-month pause. The U.S. central bank's policy-setting Federal Open Market Committee is widely expected to reduce its benchmark overnight interest rate by 25 basis points (bps) to the 4.00%-4.25% range at the conclusion of a two-day meeting on We ...