ST. LOUIS — A U.S. Supreme Court ruling this week could have a “chilling effect” on the many lawsuits filed in St. Louis claiming talcum powder causes a deadly form of cancer in women, including cases under appeal in which stricken women and their survivors have been awarded more than $300 million, experts said Tuesday.Justices ruled 8-1 Monday that hundreds of out-state-residents can’t sue Bristol-Myers Squibb Co. in California state court over adverse reactions to the blood thinner Plavix.It …