New glibc-testfail io/tst-copy_file_range with kernel-next.

[Florian Weimer]

* Stefan Liebler:

> as information, I had the chance to run the glibc-testsuite on a
> kernel-next from today on s390x and recognized a new failing test:
> io/tst-copy_file_range

Thanks for looking at this and summarizing the changes.

There's been a previous thread here:

  <https://sourceware.org/ml/libc-alpha/2019-06/msg00039.html>

I can back out the emulation, as discussed, then there wouldn't be
anything left to test in theory (although I think our tests caught one
or two bugs in XFS backports downstream, that as before fstests covered
copy_file_range).

It's not easy for me to test linux-next, but I can try to tweak the test
so that it copes with the different error codes.

The cross-device test we should just drop.

Thanks,
Florian