LU-18394 test: adjust step for different OS Arch

LU-18394 test: adjust step for different OS Arch

in test_49 of sanity-quota, the Bash could fail if the data to be
processsed by "eval" is big under PPC64le, decrease the data size
to be suitable for different Arches.

Test-Parameters: trivial testlist=sanity-quota env=SLOW=yes,ONLY=49,ONLY_REPEAT=10 clientdistro=el8.9 clientarch=ppc64le serverdistro=el8.8
Signed-off-by: Hongchao Zhang <hongchao@whamcloud.com>
Change-Id: I6fef841211662c3518caf97835598dc26beaea1f
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/56820
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>