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

Bắt đầu từ nhánh nhanh sendfile của shutil.copyfile và xem xét cách các lỗi của os.sendfile được xử lý. Tái hiện lỗi bằng shutil.copyfile('src', 'dst') trên hệ thống tệp bị ảnh hưởng; được coi là hoàn tất khi lỗi ENODATA chuyển sang đường dẫn sao chép đọc/ghi tiêu chuẩn.