Investors in financial markets who had bet oil prices would keep falling and the U.S. dollar would keep climbing saw their trades backfire in April, Tommy Stubbington and Christian Berthelsen report. The U.S. benchmark crude oil price ended up soaring 25% after falling 11% in the first three months of the year. Quick cutbacks by U.S. shale-oil producers and a slowdown in U.S. growth were a couple of the surprise factors behind the turnabout across stock, bond, currency and commodity markets. […]