How to hibernate MacBook Pro without a battery
It turns out that my sleep image was somehow corrupted and system couldn’t boot from it correctly. After I’ve deleted it, all started working fine again: closing the lid and waiting for the light indicator to start pulsing, disconnected charger, connected it again and system restored from disk just fine.

Previously, I was been able to work around this issue by using DeepSleep utility, that was recommended as alternative approach on How to Hibernate a Mac. 

When I want to unplug my MacBook from power I use DeepSleep to hibernate to disk. The resume then works the same like I remember it from when I had a battery in my machine. ¯\_(ツ)_/¯