CoreFoundation: remove CFURLSessionInterface from CF
CoreFoundation: remove CFURLSessionInterface from CF

This has been isolated to CFURLInterface, remove the duplicated code.

apple/swift-corelibs-foundation,e78l/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,e78l/swift-corelibs-foundation,e78l/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,e78l/swift-corelibs-foundation,e78l/swift-corelibs-foundation