The sort before tended to be alphabetical, which put test
`8_force_delete_snapshot` after `815_sync_out-of-order_snapshots`, but
`8` should come before `815`.
Before:
```
root@demo:~/sanoid/tests/syncoid# ./run-tests.sh
Running test 1_bookmark_replication_intermediate ... [PASS]
Running test 2_bookmark_replication_no_intermediate ... [PASS]
Running test 3_force_delete ... [PASS]
Running test 4_bookmark_replication_edge_case ... [PASS]
Running test 5_reset_resume_state ... mbuffer: error: outputThread: error writing to <stdout> at offset 0x90000: Broken pipe
mbuffer: warning: error during output to <stdout>: Broken pipe
[PASS]
Running test 6_reset_resume_state2 ... [PASS]
Running test 7_preserve_recordsize ... [PASS]
Running test 815_sync_out-of-order_snapshots ... [PASS]
Running test 8_force_delete_snapshot ... [PASS]
```
After:
```
root@demo:~/sanoid/tests/syncoid# ./run-tests.sh
Running test 1_bookmark_replication_intermediate ... [PASS]
Running test 2_bookmark_replication_no_intermediate ... [PASS]
Running test 3_force_delete ... [PASS]
Running test 4_bookmark_replication_edge_case ... [PASS]
Running test 5_reset_resume_state ... mbuffer: error: outputThread: error writing to <stdout> at offset 0xf0000: Broken pipe
mbuffer: warning: error during output to <stdout>: Broken pipe
[PASS]
Running test 6_reset_resume_state2 ... [PASS]
Running test 7_preserve_recordsize ... [PASS]
Running test 8_force_delete_snapshot ... [PASS]
Running test 815_sync_out-of-order_snapshots ... [PASS]
```