Starting ad hoc process with no start node and auto start does not properly handle first node instance id

When adhoc process is modeled as a case without any start nodes and some nodes are marked as auto start the first node that will be activated will get node instance id 0 but that is then considered as unset id - as default value for primitive long.

That will lead to duplicated node instance id when node instance is read from db by marshaller and thus gets new node instance id. Next this will be logged in db (nodeInstanceLog table) that will have two entries for same not with different node instances leading to always having a task being active even tough it was already completed.