Merge bitcoin/bitcoin#28412: test: remove unused variables in p2p_invalid_block

3eb0380 test: remove unused variables in `p2p_invalid_block` (brunoerg)

Pull request description:

ACKs for top commit:
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    ACK 3eb0380

Tree-SHA512: eadae1eb323e5562d1ea0aed43ebf0145f0fdbb6cd6d4646bbf1ca89f384820e7b9cb69f0bb04a949e9f8983a879aee8387d6f7ac3d4e4ea027f8892e656fb98

Author: fanquake

test/functional/p2p_invalid_block.py

@@ -46,12 +46,10 @@ def run_test(self):
 
         self.log.info("Create a new block with an anyone-can-spend coinbase")
 
-        height = 1
         block = create_block(tip, create_coinbase(height), block_time)
         block.solve()
         # Save the coinbase for later
         block1 = block
-        tip = block.sha256
         peer.send_blocks_and_test([block1], node, success=True)
 
         self.log.info("Mature the block.")