#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
import java.util.function.LongSupplier;
import java.util.function.Supplier;
import java.util.function.UnaryOperator;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import static java.util.Collections.emptyList;
import static java.util.Collections.emptySet;
import static java.util.Collections.singleton;
import static org.elasticsearch.cluster.coordination.AbstractCoordinatorTestCase.Cluster.DEFAULT_DELAY_VARIABILITY;
import static org.elasticsearch.cluster.coordination.ClusterBootstrapService.BOOTSTRAP_PLACEHOLDER_PREFIX;
import static org.elasticsearch.cluster.coordination.CoordinationStateTestCluster.clusterState;
import static org.elasticsearch.cluster.coordination.Coordinator.Mode.CANDIDATE;
import static org.elasticsearch.cluster.coordination.Coordinator.Mode.FOLLOWER;
import static org.elasticsearch.cluster.coordination.Coordinator.Mode.LEADER;
import static org.elasticsearch.cluster.coordination.Coordinator.PUBLISH_TIMEOUT_SETTING;
import static org.elasticsearch.cluster.coordination.ElectionSchedulerFactory.ELECTION_BACK_OFF_TIME_SETTING;
import static org.elasticsearch.cluster.coordination.ElectionSchedulerFactory.ELECTION_DURATION_SETTING;
import static org.elasticsearch.cluster.coordination.ElectionSchedulerFactory.ELECTION_INITIAL_TIMEOUT_SETTING;
import static org.elasticsearch.cluster.coordination.FollowersChecker.FOLLOWER_CHECK_INTERVAL_SETTING;
import static org.elasticsearch.cluster.coordination.FollowersChecker.FOLLOWER_CHECK_RETRY_COUNT_SETTING;
import static org.elasticsearch.cluster.coordination.FollowersChecker.FOLLOWER_CHECK_TIMEOUT_SETTING;
import static org.elasticsearch.cluster.coordination.LeaderChecker.LEADER_CHECK_INTERVAL_SETTING;
import static org.elasticsearch.cluster.coordination.LeaderChecker.LEADER_CHECK_RETRY_COUNT_SETTING;
import static org.elasticsearch.cluster.coordination.LeaderChecker.LEADER_CHECK_TIMEOUT_SETTING;
import static org.elasticsearch.cluster.coordination.NoMasterBlockService.NO_MASTER_BLOCK_ID;
import static org.elasticsearch.cluster.coordination.Reconfigurator.CLUSTER_AUTO_SHRINK_VOTING_CONFIGURATION;
import static org.elasticsearch.core.Strings.format;
import static org.elasticsearch.discovery.PeerFinder.DISCOVERY_FIND_PEERS_INTERVAL_SETTING;
import static org.elasticsearch.gateway.GatewayService.STATE_NOT_RECOVERED_BLOCK;
import static org.elasticsearch.monitor.StatusInfo.Status.HEALTHY;