dddd09eb33d14fabda0aa40fa008b23b2bd6e589 test: Wait until mempool is loaded in wallet_abandonconflict (MarcoFalke)
Pull request description:
This might or might not fix intermittent issues such as https://ci.appveyor.com/project/DrahtBot/bitcoin/builds/28724018#L4091 I believe the mempool was not loaded fully after the restart, in which case it was not dumped either on the next restart. Thus, the previous mempool was attempted to be loaded a second time, which succeeded and contained the txs.
Backport of Core PR17522