dmu_objset: replace dnode_hash impl with cityhash4
#4060
| Job | Run time |
|---|---|
| 12m 15s | |
| 14m 23s | |
| 7m 20s | |
| 27m 50s | |
| 8m 24s | |
| 1h 16m 16s | |
| 1h 15m 34s | |
| 1h 36m 59s | |
| 39m 38s | |
| 25m 7s | |
| 1h 0m 33s | |
| 1h 27m 7s | |
| 36m 51s | |
| 57m 23s | |
| 7s | |
| 10h 25m 47s |