By Alexandra Alper WASHINGTON (Reuters) – U.S. senators have scaled back a proposal that placed new curbs on the use of Chinese-made chips by the U.S. government and its contractors, according to a recent draft seen by Reuters, amid pushback from trade groups like the U.S. Chamber of Commerce. The move is the latest example of industry’s efforts to weaken proposals aimed at crimping China’s burgeoning tech sector, by pointing out how such measures will raise costs. Top Senate Democrat Chuck Schumer and John Cornyn, a prominent Republican China hawk, unveiled a measure in September that would h…