By Herbert Lash NEW YORK (Reuters) – The New York Stock Exchange tested its trading systems over the summer to make sure Alibaba Group Holding Ltd’s market debut on Friday goes without a hitch, after the Chinese e-commerce company’s initial public offering raised $21.8 billion. Alibaba chose the NYSE over rival exchange operator Nasdaq OMX Group Inc to list its shares in part because it worried about Nasdaq’s ability to handle a massive IPO after Facebook Inc’s botched market debut in 2012, sources have previously said. …