U.S. economic growth is expected to accelerate this year and next, yet remain modest, even if President Trump’s promised tax cuts and infrastructure spending are implemented, a survey found. The economy will grow a solid 2.3 percent this year and 2.5 percent in 2018, according to 50 economists surveyed by the National Association for Business Economics. Those rates would be up from 2016’s anemic pace of 1.6 percent. Still, those rates are below the 3 percent to 4 percent growth that Trump has promised to bring about through steep corporate and individual tax cuts and more spending on roads, airports...