NAT entries go missing if switch zone is restarted in early networking. #6068
Description
In #5037 and #4650 we noticed an issue where NAT entires would not be fully populated on scrimlet reboot. This is because the entity making these entries is the sled agent launching a zone that requires NAT entries. Further analysis is provided in #4857. However, the aforementioned rely on Nexus and RPW machinery to create an eventually consistent NAT situation. If nexus is not running, we have no recourse in early networking and are left without critical NAT entries needed for things like time synchronization.