Merge #18609: test: Remove REJECT message code

b1b0cfecb6 test: Remove REJECT message code (Hennadii Stepanov)

Pull request description:

  We no longer use REJECT p2p message:
  - #15437
  - #17004

ACKs for top commit:
  theStack:
    ACK https://github.com/bitcoin/bitcoin/pull/18609/commits/b1b0cfecb639ce44be280c7a45a41a19e893c401 (nice dead code find)

Tree-SHA512: 0a662b282e921c3991aeb15f54d077837f1ef20bc2e3b0b35117bb97a21d1bd1c3e21458e5c18ba0ca02030d559e3e8e74dbd3d3e2b46dbe7bede550948c3b55

test/functional/test_framework/mininode.py

@@ -339,7 +339,6 @@ class P2PInterface(P2PConnection):
     def on_merkleblock(self, message): pass
     def on_notfound(self, message): pass
     def on_pong(self, message): pass
-    def on_reject(self, message): pass
     def on_sendcmpct(self, message): pass
     def on_sendheaders(self, message): pass
     def on_tx(self, message): pass