Wait for sporks to propagate in llmq-chainlocks.py before mining new blocks (dashpay#3168)

The bug was introduced in dashpay@e5ebabe

Author: UdjinM6

test/functional/llmq-chainlocks.py

@@ -41,6 +41,7 @@ def run_test(self):
             self.mine_quorum()
 
         self.nodes[0].spork("SPORK_19_CHAINLOCKS_ENABLED", 0)
+        self.wait_for_sporks_same()
 
         self.log.info("Mine single block, wait for chainlock")
         self.nodes[0].generate(1)