#98420 verifies that the election scheduler is not running when a cluster is stable, but this assertion does not hold in the `AtomicRegisterCoordinatorTests` suite. This issue tracks the work to investigate and fix up the problem.
test/framework/src/main/java/org/elasticsearch/cluster/coordination/AbstractCoordinatorTestCase.java
ClusterNode getAnyNode() {
            return getAnyNodeExcept();
        }
        ClusterNode getAnyNodeExcept(ClusterNode... clusterNodesToExclude) {
            List<ClusterNode> filteredNodes = getAllNodesExcept(clusterNodesToExclude);
            assert filteredNodes.isEmpty() == false;
            return randomFrom(filteredNodes);
        }
        List<ClusterNode> getAllNodesExcept(ClusterNode... clusterNodesToExclude) {
            Set<String> forbiddenIds = Arrays.stream(clusterNodesToExclude).map(ClusterNode::getId).collect(Collectors.toSet());
            return this.clusterNodes.stream().filter(n -> forbiddenIds.contains(n.getId()) == false).collect(Collectors.toList());
        }
        ClusterNode getAnyNodePreferringLeaders() {
            for (int i = 0; i < 3; i++) {
                ClusterNode clusterNode = getAnyNode();
                if (clusterNode.coordinator.getMode() == LEADER) {
                    return clusterNode;
                }
            }
            return getAnyNode();
        }
        void setEmptySeedHostsList() {
            seedHostsList = emptyList();
        }
        void blackholeConnectionsFrom(ClusterNode sender, ClusterNode destination) {
            blackholedConnections.add(Tuple.tuple(sender.getId(), destination.getId()));
        }
        void clearBlackholedConnections() {
            blackholedConnections.clear();
        }