[backport#14193][test] Add test to check mempool consistency in case of reorgs

Summary:
https://github.com/bitcoin/bitcoin/pull/14193/commits/fa2b083c3feb0522baf652045efa6b73458761a3

Depends on D6539

Concludes backport of Core PR14193

Test Plan:

cmake -DCMAKE_BUILD_TYPE=Debug
ninja check check-functional

Reviewers: #bitcoin_abc, deadalnix

Reviewed By: #bitcoin_abc, deadalnix

Differential Revision: https://reviews.bitcoinabc.org/D7440