This reverts commit db776b07.

More then one builder can be called in same time for same invoice.

Delivery is stopped so invoice simulation WILL be present.

Let the activity system chose randomly what to do.

Scenario is used one, so just do it inline.

Side effect of returning self slave in slave list is used in SlapTool.

Narrow to only return Slave Instance related delivery lines.

_checkComputerPartitionSalePackingListState is fine tuned and selects only
delivery lines related to computer partition *and* software instance.

Slave instances are again in intereset.