LU-17010 lfsck: don't dump stack repeatedly

LU-17010 lfsck: don't dump stack repeatedly

If there are transactions started with LFSCK in dry-run mode, don't
dump the stack repeatedly, as this can spam the console logs and
significantly hurt performance.

Lustre-commit: dc360cd3eff20618f243ab89097a62f8ecf2c929
Lustre-change: https://review.whamcloud.com/52356

Test-Parameters: trivial testlist=sanity-lfsck
Fixes: 0c1ae1cb9c ("LU-13124 scrub: check for multiple linked file")
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: I0b0d64911453dc8ab947e284656311b5d0300c1e
Reviewed-by: Hongchao Zhang <hongchao@whamcloud.com>
Reviewed-by: Lai Siyao <lai.siyao@whamcloud.com>