LU-16788 tests: sanity should remove temp files

LU-16788 tests: sanity should remove temp files

during the test to fit OSTSIZE

Test-Parameters: trivial
Signed-off-by: Alex Zhuravlev <bzzz@whamcloud.com>
Change-Id: I2f1cfe0511061794d81d0349cf36a50f40470553
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/50819
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>