message: test: Fix intermittent issue in wallet_listsinceblock
diff: @@ -191,6 +191,7 @@ class ListSinceBlockTest(BitcoinTestFramework):
  address = key_to_p2wpkh(eckey.get_pubkey().get_bytes())
  self.nodes[2].sendtoaddress(address, 10)
  self.nodes[2].generate(6)
  + self.sync_all()
  self.nodes[2].importprivkey(privkey)
  utxos = self.nodes[2].listunspent()
  utxo = [u for u in utxos if u["address"] == address][0]
  