LONDON (Reuters) - Wall Street looked set for a surge on Wednesday and global stocks rose after sharp U.S. election gains for the opposition Democrats, but the outcome, which casts doubt on further tax cuts, hit the dollar and sent Treasury yields lower.The Democrats looked headed for a gain of more than 30 seats, well beyond the 23 they needed to claim their first majority in the House in eight years. With President Donald Trump's Republican party holding onto its Senate majority, the results..