6419701: DefaultFileManager clean up: URI.create
6483788: DefaultFileManager.ZipFileObject.toUri() fails to escape space characters
6501502: JSR 199: FileObject.toUri should return file:///c:/ or file:/c:/ not file://c:/
6877206: JavaFileObject.toUri returns bogus URI (win)
6877223: tests @ignored because of issues with File.toURI on Windows
Reviewed-by: mcimadamore, alanb