LU-16256 tests: sanity-flr to remove temp files

LU-16256 tests: sanity-flr to remove temp files

this let the test run on a smaller devices.

Test-Parameters: trivial testlist=sanity-flr
Signed-off-by: Alex Zhuravlev <bzzz@whamcloud.com>
Change-Id: I800bcb7a8d847e1f0d44f344c3810ef298c8507a
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/48922
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>