scripted-diff: Use generate* from TestFramework

-BEGIN VERIFY SCRIPT-
 sed --regexp-extended -i \
     's/((self\.)?(nodes\[[^]]+\]|[a-z_]*(wallet|node)[0-9a-z_]*))\.(generate(|toaddress|block|todescriptor)(\(|, ))/self.\5\1, /g' \
     $(git grep -l generate ./test | grep -v 'test_framework/' | grep -v 'feature_rbf')
-END VERIFY SCRIPT-

test/functional/mempool_expiry.py

@@ -36,8 +36,8 @@ class MempoolExpiryTest(BitcoinTestFramework):
         self.wallet = MiniWallet(node)
 
         # Add enough mature utxos to the wallet so that all txs spend confirmed coins.
-        self.wallet.generate(4)
-        node.generate(COINBASE_MATURITY)
+        self.generate(self.wallet, 4)
+        self.generate(node, COINBASE_MATURITY)
 
         # Send a parent transaction that will expire.
         parent_txid = self.wallet.send_self_transfer(from_node=node)['txid']