Foundation: change Data.Indices to be a CountableRange<Int>, that is much faster than the default
Foundation: change Data.Indices to be a CountableRange<Int>, that is much faster than the default

apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation