[test] Fix nits leftover from 11771

Remove unused variable reassignments in p2p_invalid_tx.py and call
send_txs_and_test() with valid transaction.

Author: conscott

test/functional/p2p_invalid_tx.py

@@ -33,12 +33,10 @@ 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_time += 1
         block.solve()
         # Save the coinbase for later
         block1 = block
         tip = block.sha256
-        height += 1
         node.p2p.send_blocks_and_test([block], node, success=True)
 
         self.log.info("Mature the block.")
@@ -49,7 +47,10 @@ def run_test(self):
         tx1 = create_transaction(block1.vtx[0], 0, b'\x64', 50 * COIN - 12000)
         node.p2p.send_txs_and_test([tx1], node, success=False, reject_code=16, reject_reason=b'mandatory-script-verify-flag-failed (Invalid OP_IF construction)')
 
-        # TODO: test further transactions...
+        # Verify valid transaction
+        tx1 = create_transaction(block1.vtx[0], 0, b'', 50 * COIN - 12000)
+        node.p2p.send_txs_and_test([tx1], node, success=True)
+
 
 if __name__ == '__main__':
     InvalidTxRequestTest().main()