(fs) UserDefinedFileAttributeView no longer works with long path (win)

The changes in JDK-8273922 introduce a regression for cases with long file paths.

We need to introduce a getPathWithPrefixForWin32Calls or some such method that returns the file path with the \\?\ prefix, then appends the ":<name>".

We also need to expand our tests in this area, it seems that existing long path tests do not include access to user defined attributes.