Fix portability of `sendfile(2)` support detection for Lustre filesystems

Bug report

Bug description:

On Lustre on Linux (specifically the AWS implementation) there is a rare and difficult to reproduce failure of shutil.copyfile in its sendfile(2) fast path because the syscall returns ENODATA. The situation is recoverable by falling back to the standard read/write file copy (patch forthcoming).

Reproducing the bug requires the filesystem to be in a specific state which I have not been able to reproduce at will but we've seen it on occasions by multiple users. Additionally similar bug has been seen on rust fs::copy which similarly does not trap the ENODATA error.

Following is sufficient to reproduce bug for the specific (rare) file that fails:

import shutil
shutil.copyfile('src', 'dst')

error:

sent = os.sendfile(outfd, infd, offset, blocksize)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
OSError: [Errno 61] No data available: '/shared/fsx1/filename' 

CPython versions tested on:

3.14

Operating systems tested on:

Linux

Linked PRs

• gh-139417

Commencez par le chemin rapide sendfile de shutil.copyfile et examinez la manière dont les erreurs de os.sendfile sont gérées. Reproduisez l’échec avec shutil.copyfile('src', 'dst') sur le système de fichiers concerné ; le travail est terminé lorsqu’un échec ENODATA revient au chemin de copie standard en lecture/écriture.