obd test sysbench should support run multiple times with different threads

In normal, it will run one test with different threads  like this
```
obd test sysbench obperf --component=obproxy --tenant=perf --script-name=oltp_read_only.lua --table-size=1000000 --threads=32/64/128/256/512/1024
```

you can define the format as 32/64/128/256/512/1024 or 32&64&128&256&512&1024 or json format [32,64,128,256,512,1024]