MRG: fix multigather output by adding md5sum along with -U/--output-add-query-md5sum
#6321
| Job | Run time |
|---|---|
| 2m 10s | |
| 8m 31s | |
| 6m 39s | |
| 7m 46s | |
| 0s | |
| 25m 6s |