EX-9125 tests: get stats_compr param in sanity-compr/1007

EX-9125 tests: get stats_compr param in sanity-compr/1007

This patch adds getting stats_compr param in sanity-compr
test 1007 and 1008 to track data compression statistics.

Test-Parameters: trivial testlist=sanity-compr env=ONLY="1007 1008",ONLY_REPEAT=3

Change-Id: I7df25d36c8c89ec5a568bf1e8d5694a97dd18ecc
Signed-off-by: Jian Yu <yujian@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/53927
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Vitaliy Kuznetsov <vkuznetsov@ddn.com>