By Matthias Inverardi and Marta Orosz BONN, Germany (Reuters) -A tax lawyer, alleged to have masterminded one of Germany’s biggest post-war frauds, was sentenced to eight years in jail on Tuesday after a landmark trial that has gripped the country. Hanno Berger, a 72-year-old former tax inspector turned legal tax expert, is the most high profile professional to be convicted after sprawling investigations into the cum-ex dividend stripping scheme, which some experts estimate has cost German taxpayers around 10 billion euros ($10.5 billion). Berger, who fled to Switzerland in 2012 before being e…