validation: Move invalid block handling to CChainState

Summary:
Notes:

• InvalidChainFound was already moved to CChainState in D7573
• CheckForkWarningConditionsOnNewFork was removed by core in core#19905 because it doesn't work, but in Bitcoin ABC it was fixed in D1950.

This is a backport of core#21055 [8/16]
https://github.com/bitcoin/bitcoin/pull/21055/commits/8b99efbcc08ab41caf657c6d730a27e6a91bc356

Test Plan: ninja all check-all

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D11213