test for --shutdown-on-slot-synced

[dorin100]

details here - IntersectMBO/cardano-node#3670

[mkoura]

Who is using this functionality? IMHO this very low priority test, if it is worth implementing at all :-) It would be exactly the same test is already implemented in cardano-node.

[dorin100]

I don't expect it to be a widely used functionality but like anything we make publicly available, it might and will be used by the community too, so having a test for it in our regression would make sense.

I agree that compared with the other tasks in our backlog this has a lower priority.