Add fork block checkpoints and update defaultAssumedValid and min chain work (main and testnet)
Summary:
Changes to chain params:
- added fork block checkpoints for mainnet and testnet3
- update defaultAssumeValid for both chains
- updated nMinimumChainWork to match the defaultAssumeValid blocks
Having a check point on fork block means nodes cannot be led onto wrong
UAHF-compatible chain.
Knowing that you are on right Bitcoin Cash chain after the fork block
can be used to optimize some code which determines whether we are pre-fork
or post-fork.
Test Plan:
make check
Run bitcoind with the changes on mainnet and testnet
Reviewers: #bitcoin_abc, deadalnix, sickpig
Reviewed By: #bitcoin_abc, deadalnix, sickpig
Subscribers: sickpig
Differential Revision: https://reviews.bitcoinabc.org/D480