Require CBlockIndex::RaiseValidity() to hold cs_main

Summary:
This is a partial backport of core#22932
https://github.com/bitcoin/bitcoin/pull/22932/commits/e9f3aa5f6a7b39e8d5f2069617e5e382798d8d60

Depends on D13033

Test Plan:
With clang and DEBUG:

ninja all check-all bitcoin-fuzzers

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D13034