[qa] Remove hardcoded "4 nodes" from test_framework

qa/rpc-tests/nodehandling.py

@@ -14,6 +14,12 @@ import http.client
 import urllib.parse
 
 class NodeHandlingTest (BitcoinTestFramework):
+
+    def __init__(self):
+        super().__init__()
+        self.num_nodes = 4
+        self.setup_clean_chain = False
+
     def run_test(self):
         ###########################
         # setban/listbanned tests #