test: Remove from_node from create_self_transfer* MiniWallet helpers

The from_node argument is no longer used as of commit
a55606c3bd

test/functional/test_framework/util.py

@@ -527,9 +527,8 @@ def create_lots_of_big_transactions(mini_wallet, node, fee, tx_batch_size, txout
     use_internal_utxos = utxos is None
     for _ in range(tx_batch_size):
         tx = mini_wallet.create_self_transfer(
-                from_node=node,
-                utxo_to_spend=None if use_internal_utxos else utxos.pop(),
-                fee_rate=0,
+            utxo_to_spend=None if use_internal_utxos else utxos.pop(),
+            fee_rate=0,
         )["tx"]
         tx.vout[0].nValue -= fee_sats
         tx.vout.extend(txouts)