[3.12] gh-120226: Fix test_sendfile_close_peer_in_the_middle_of_receiving on Linux >= 6.10 (GH-120227) (#123422)

gh-120226: Fix test_sendfile_close_peer_in_the_middle_of_receiving on Linux >= 6.10 (GH-120227)

The worst case is that the kernel buffers 17 pages with a page size of 64k.
(cherry picked from commit a7584245661102a5768c643fbd7db8395fd3c90e)

Co-authored-by: Xi Ruoyao <xry111@xry111.site>