test: fix: remove outdated TestNode.generate calls

Currently failing on CI. After this change the test itself still fails,
but at least it's apparently for a non-incidental reason.

Author: jamesob

test/functional/wallet_listtransactions.py

@@ -244,17 +244,17 @@ def run_externally_generated_address_test(self):
         self.log.info("Send to externally generated addresses")
         # send to an address beyond the next to be generated to test the keypool gap
         self.nodes[1].sendtoaddress(addr3, "0.001")
-        self.nodes[1].generate(1)
+        self.generate(self.nodes[1], 1)
         self.sync_all()
 
         # send to an address that is already marked as used due to the keypool gap mechanics
         self.nodes[1].sendtoaddress(addr2, "0.001")
-        self.nodes[1].generate(1)
+        self.generate(self.nodes[1], 1)
         self.sync_all()
 
         # send to self transaction
         self.nodes[0].sendtoaddress(addr1, "0.001")
-        self.nodes[0].generate(1)
+        self.generate(self.nodes[0], 1)
         self.sync_all()
 
         self.log.info("Verify listtransactions is the same regardless of where the address was generated")