nfs: test nfs4_getfacl near page size ACL from server

nfs: test nfs4_getfacl near page size ACL from server

Test nfs4_getfacl gets ACL list correctly from server when the ACL
length is close enough to the end of a page. On buggy NFS client
getxattr could return ERANGE. Upstream commit ed92d8c137b7 ("NFSv4:
fix getacl ERANGE for some ACL buffer sizes") fixed this bug in 4.11
kernel.

Note that this reproducer was originally written by J. Bruce Fields.

Cc: J. Bruce Fields <bfields@redhat.com>
Cc: Weston Andros Adamson <dros@primarydata.com>
Cc: linux-nfs@vger.kernel.org
Reviewed-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>