Merge bitcoin/bitcoin#22313: test: Add missing sync_all to feature_coinstatsindex

fafd916 test: Add missing sync_all to feature_coinstatsindex (MarcoFalke)

Pull request description:

  Sync the blocks before invalidating them to ensure all nodes are on the right tip. Otherwise nodes[0] might stay on the "stale" block and the test fails (intermittently)

ACKs for top commit:
  jamesob:
    crACK bitcoin/bitcoin@fafd916

Tree-SHA512: ca567b97b839b56c91d52831eaac18d8c843d376be90c9fd8b49d2eb4a46b801a1d2402996d5dfe2bef3e2c9bd75d19ed443e3f42cc4679c5f20043ba556efc8

Author: MarcoFalke

test/functional/feature_coinstatsindex.py

@@ -281,6 +281,7 @@ def _test_reorg_index(self):
         # Add another block, so we don't depend on reconsiderblock remembering which
         # blocks were touched by invalidateblock
         index_node.generate(1)
+        self.sync_all()
 
         # Ensure that removing and re-adding blocks yields consistent results
         block = index_node.getblockhash(99)