=per #15520 make Persist1CommandProcessor in benchmark  extends Persiste...

sorry for my previous PR https://github.com/akka/akka/pull/15517 not that right,I corrected this via this one.
now the Persist1CommandProcessor extends the PersistentActor and not ```persist```message.
maybe,cause the previous one extends the ```PersistentActor```,but later after I change it I recognized that you just deprecated the ```Processor```,so how about add two test ,one for ```Processor```,and one for ```PersistentActor``` for the command sourcing?
In fact this is my second line of scala,sheer curve to learn.