Flip the switch on 'private' and 'fileprivate'.
Flip the switch on 'private' and 'fileprivate'.

Merge pull request #3767 from jrose-apple/private-and-fileprivate
apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation