CorruptionPossible -> BLOCK_MUTATED

Summary:
Co-authored-by: Anthony Towns <aj@erisian.com.au>

This is a partial backport of Core PR15141 : https://github.com/bitcoin/bitcoin/pull/15141/commits/9ab2a0412e96e87956fe61257387683635213035

Test Plan:

ninja all check-all

Reviewers: #bitcoin_abc, majcosta

Reviewed By: #bitcoin_abc, majcosta

Differential Revision: https://reviews.bitcoinabc.org/D6707