test: add coverage for the incremental budget sync flow.
test: add coverage for the incremental budget sync flow.

Essentially a node dropping the budget data and waiting until any of the connected peers relays the complete budget data once more (this happens every 28 blocks in regtest).

PIVX-Project/PIVX,PIVX-Project/PIVX,PIVX-Project/PIVX,PIVX-Project/PIVX,PIVX-Project/PIVX,PIVX-Project/PIVX,PIVX-Project/PIVX,PIVX-Project/PIVX,PIVX-Project/PIVX