Enhance Test HTTP Server
Enhance Test HTTP Server

- Add support for URL parameters.

- Add status code URLs for /xxx to allow specifiing specific codes
  including setting the Location header for 3xx codes.

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