By Alastair Sharp TORONTO (Reuters) – Canada’s main stock index edged lower on Wednesday, with gains from some big energy producers offset by dips in heavyweight banks and a pullback in Valeant Pharmaceuticals International Inc shares after an acquisition-backed bump. Suncor Energy Inc gained 2.6 percent to C$41.37 and Canadian Natural Resources Ltd added 0.7 percent to C$32.66 even as record U.S. crude inventories hurt oil prices. …