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/feature_presegwit_node_upgrade.py

@@ -28,7 +28,7 @@ class SegwitUpgradeTest(BitcoinTestFramework):
         assert not softfork_active(node, "segwit")
 
         # Generate 8 blocks without witness data
-        node.generate(8)
+        self.generate(node, 8)
         assert_equal(node.getblockcount(), 8)
 
         self.stop_node(0)