Add tests for the Branch and Bound algorithm
Summary:
This ia partial backport of Core PR10637 : https://github.com/bitcoin/bitcoin/pull/10637/commits/4566ab75f277612425337bf7786c1d3a410d894a
Depends on D3250
Test Plan:
make check
Reviewers: #bitcoin_abc, Fabien
Reviewed By: #bitcoin_abc, Fabien
Subscribers: Fabien
Differential Revision: https://reviews.bitcoinabc.org/D3252