LU-18344 test: sanity test_247f interop fix

LU-18344 test: sanity test_247f interop fix

2.16 always enables remote subdir mount, update sanity test_247f.

Test-Parameters: trivial
Signed-off-by: Lai Siyao <lai.siyao@whamcloud.com>
Change-Id: Ibe04d307a5596a6047d5fd301e19c33bf07f1e21
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/56733
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Emoly Liu <emoly@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>