Change ++ to += 1 based on swift proposal SE-0004
Change ++ to += 1 based on swift proposal SE-0004

tiagomartinho/swift-corelibs-xctest,tiagomartinho/swift-corelibs-xctest,yoonapps/swift-corelibs-xctest,yoonapps/swift-corelibs-xctest,apple/swift-corelibs-xctest,apple/swift-corelibs-xctest