NEW YORK (Reuters) - A raft of earnings reports from consumer discretionary companies and U.S. retail sales data set for the coming week could help investors determine to what extent the coronavirus is hitting consumer demand.The S&P consumer discretionary sector has been among the index’s best performers this year, gaining about 3.4% and trailing only the technology , utilities and communications services sectors. But discretionary stocks could be in for a bumpy ride if companies warn..