Prevent auto-finalization from moving backward the finalization point
Summary:
This fix an issue where the auto-finalization behaviour could cause
unexpected rewind of the finalization chain by an amount of
maxreorgdepth blocks.
Depends on D2130
Test Plan:
./test/functional/abc-finalize-block.py
Reviewers: deadalnix, #bitcoin_abc
Reviewed By: deadalnix, #bitcoin_abc
Subscribers: teamcity, schancel
Differential Revision: https://reviews.bitcoinabc.org/D2161