(Refiles to remove extraneous text from headline) BERLIN, April 7 (Reuters) - German laboratory services group Synlab said on Wednesday it planned to float on the stock market, offering investors exposure to a coronavirus testing boom and the consolidation of Europe’s fragmented healthcare landscape. Sources familiar with the matter have said that Synlab, owned by private equity group Cinven, could fetch a valuation of 6 billion euros ($7.1 billion) including debt when it lists in Frankfurt. Cinven bought Synlab for 1.7 billion euros in 2015 from BC Partners and merged it with France-based Labco, creating Europe’s largest lab services provider handling about 500 million tests a year.