LU-15934 tests: add a test case for update llog

LU-15934 tests: add a test case for update llog

A test case to simulate the update llog corruption
situation. It replaces the catalog file with a
random data. The recovery of mdt will be blocked
if without the fixing patch.

Lustre-change: https://review.whamcloud.com/51208
Lustre-commit: 54301fe4f598eef5aebdbdb0c7f3dddea9541c4e

Fixes: 814691bcff ("LU-15934 lod: renew the update llog")
Signed-off-by: Yang Sheng <ys@whamcloud.com>
Change-Id: I0ade8d0ff33ddc06b622e5e67cf4b4775dfff129
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Lai Siyao <lai.siyao@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/51570
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>