[tests] Don't subclass from object for Python 3

test/functional/test_framework/comptool.py

@@ -27,7 +27,7 @@ logger=logging.getLogger("TestFramework.comptool")
 
 global mininode_lock
 
-class RejectResult(object):
+class RejectResult():
     """Outcome that expects rejection of a transaction or block."""
     def __init__(self, code, reason=b''):
         self.code = code
@@ -156,13 +156,13 @@ class TestNode(NodeConnCB):
 #    across all connections.  (If outcome of final tx is specified as true
 #    or false, then only the last tx is tested against outcome.)
 
-class TestInstance(object):
+class TestInstance():
     def __init__(self, objects=None, sync_every_block=True, sync_every_tx=False):
         self.blocks_and_transactions = objects if objects else []
         self.sync_every_block = sync_every_block
         self.sync_every_tx = sync_every_tx
 
-class TestManager(object):
+class TestManager():
 
     def __init__(self, testgen, datadir):
         self.test_generator = testgen