He wasn’t a doctor or a scientist, but we could say that Garfield Schwartz built Mayo Clinic — literally. For three decades, Schwartz, a Rochester contractor, was the builder of choice for Mayo Clinic. “He built everything Mayo built during his time,” said Ken Allsen, a Rochester architectural historian. “He didn’t have a lot of competition.” And he didn’t put up only Mayo buildings. Schwartz’s construction company built schools, hotels, industr…