[backport#15758] test: Add reorg test to wallet_balance

Summary:
https://github.com/bitcoin/bitcoin/pull/15758/commits/fa79a783d63060dc6a8521c1de58b158979a59e9

Depends on D6442

Concludes backport of Core PR15758

Test Plan:

test_runner.py wallet_balance

Reviewers: #bitcoin_abc, deadalnix

Reviewed By: #bitcoin_abc, deadalnix

Differential Revision: https://reviews.bitcoinabc.org/D6443