LU-8465 e2fsck: add debug codes for multiple threads

LU-8465 e2fsck: add debug codes for multiple threads

These debug codes are added to run the multiple pass1 check
thread one by one in order. If all the codes are correct,
fsck of multiple threads should have exactly the same outcome
with single thread.

Change-Id: Ieb78a26611b3d5a4f21cc239e8616d215032c646
Signed-off-by: Li Xi <lixi@ddn.com>
Signed-off-by: Wang Shilong <wshilong@ddn.com>
Reviewed-on: https://review.whamcloud.com/36054
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>