LU-18837 tests: fix numeric comparison in sanity/101a

LU-18837 tests: fix numeric comparison in sanity/101a

Use (( ... )) instead of [[ ... ]] for numeric comparisons.

Test-Parameters: trivial
Fixes: ff78e1aa33 ("LU-4322 tests: re-enable 101a in dne config")
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: I5e210e0ca6495df4497ef7071086ef5928c267eb
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/58469
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>