Merge bitcoin#23858: test: Fix rpc_scantxoutset intermittent issue

fafe4de test: Fix pep8 of touched file (MarcoFalke)
fa0ac9d test: Fix rpc_scantxoutset intermittent issue (MarcoFalke)

Pull request description:

  I fail to see how this could have ever worked, since there is nothing that prevents the wallet from spending the coins in the utxo set.

  Fixes bitcoin#23847

  Longer term it would be nice to remove the wallet and use MiniWallet here.

ACKs for top commit:
  brunoerg:
    tACK fafe4de
  theStack:
    Code-review ACK fafe4de

Tree-SHA512: d92b7be9a81eb62f496488dd15b8e564e9b7a64b55634af2714b53f985e6a35fdae788323833ff59c40ae7c6a0cf54fe069db8eb3be03686f7c100379f54a292

Author: MarcoFalke