By Alistair Smout LONDON (Reuters) – Boris Johnson’s Conservative party faces voters in two very different parliamentary seats on Thursday, an election test that, if lost, could renew speculation about the British prime minister’s future after months of scandal. The by-elections are in deeply Conservative Tiverton and Honiton in southwest England and the normally Labour-supporting northern city of Wakefield. The diverse constituencies reflect the breadth of Johnson’s appeal in the last national election in 2019, which he won comfortably, when Wakefield voted Conservative for the first time in …