ENGINE-1655 : Make Works Serializable (2 Works : NotifyChildFinishedWork & InstantiateProcessWork)
Revert "ENGINE-1655 : Make Works Serializable (2 Works : NotifyChildFinishedWork & InstantiateProcessWork)"

This reverts commit dd28629310f65d1a108f6e065e79534dcb2fca6b.
ENGINE-1665: BPMEventHandlingJob: mark messages as "in treatment" before scheduling work.
Though, START_EVENT type SWaitingMessageEvent are not marked as "in treatment", as they can be triggered several times.
Added RestartHandler on MessageInstances + WaitingMessageEvents stuck on "in progress" when engine stopped
Merge branch 'CoreProduct'