By Padraic Halpin and Siyabonga Sishi DUBLIN/JOHANNESBURG (Reuters) -Ryanair is requiring South African passengers to prove their nationality before travelling by completing a test in Afrikaans, a language used by just 12% of the population that has long been identified with apartheid and the white minority. Europe’s largest airline by passenger numbers, which does not operate flights to and from South Africa, said it required any UK-bound passengers from the country to fill in the “simple questionnaire” due to what it described as a high prevalence of fraudulent South African passports. “If t…