[test] P2P functional test for certain fingerprinting protections

test/functional/test_framework/mininode.py

@@ -1310,8 +1310,8 @@ class msg_getheaders(object):
 class msg_headers(object):
     command = b"headers"
 
-    def __init__(self):
-        self.headers = []
+    def __init__(self, headers=None):
+        self.headers = headers if headers is not None else []
 
     def deserialize(self, f):
         # comment in bitcoind indicates these should be deserialized as blocks