### CI Link

https://gradle-enterprise.elastic.co/s/yckwl5zjomfas

### Repro line

```
./gradlew ':server:test' --tests "org.elasticsearch.cluster.coordination.CoordinatorTests.testSingleNodeDiscoveryStabilisesEvenWhenDisrupted" -Dtests.seed=949AB28501F8ED37:BBC20DD1A5D4EF81
```

### Does it reproduce?

Yes

### Applicable branches

main

### Failure history

https://ci-stats.elastic.co/s/jenkins/goto/da1547f0-2ea6-11ed-8233-4bd40c8511bb - 3 similar-looking failures over the last 90 days

### Failure excerpt

```org.elasticsearch.cluster.coordination.CoordinatorTests > testSingleNodeDiscoveryStabilisesEvenWhenDisrupted FAILED
    java.lang.AssertionError: leaders
    Expected: not an empty collection
         but: was <[]>
        at __randomizedtesting.SeedInfo.seed([949AB28501F8ED37:BBC20DD1A5D4EF81]:0)
        at org.hamcrest.MatcherAssert.assertThat(MatcherAssert.java:18)
        at org.junit.Assert.assertThat(Assert.java:956)
        at org.elasticsearch.cluster.coordination.AbstractCoordinatorTestCase$Cluster.getAnyLeader(AbstractCoordinatorTestCase.java:791)
        at org.elasticsearch.cluster.coordination.CoordinatorTests.testSingleNodeDiscoveryStabilisesEvenWhenDisrupted(CoordinatorTests.java:1939)


Suite: Test class org.elasticsearch.cluster.coordination.CoordinatorTests
  2> REPRODUCE WITH: ./gradlew ':server:test' --tests "org.elasticsearch.cluster.coordination.CoordinatorTests.testSingleNodeDiscoveryStabilisesEvenWhenDisrupted" -Dtests.seed=949AB28501F8ED37 -Dtests.locale=en-AU -Dtests.timezone=Europe/Vienna -Druntime.java=18
  2> java.lang.AssertionError: leaders
    Expected: not an empty collection
         but: was <[]>
        at __randomizedtesting.SeedInfo.seed([949AB28501F8ED37:BBC20DD1A5D4EF81]:0)
        at org.hamcrest.MatcherAssert.assertThat(MatcherAssert.java:18)
        at org.junit.Assert.assertThat(Assert.java:956)
        at org.elasticsearch.cluster.coordination.AbstractCoordinatorTestCase$Cluster.getAnyLeader(AbstractCoordinatorTestCase.java:791)
        at org.elasticsearch.cluster.coordination.CoordinatorTests.testSingleNodeDiscoveryStabilisesEvenWhenDisrupted(CoordinatorTests.java:1939)
  2> NOTE: leaving temporary files on disk at: /home/davidturner/src/elasticsearch/server/build/testrun/test/temp/org.elasticsearch.cluster.coordination.CoordinatorTests_949AB28501F8ED37-002
  2> NOTE: test params are: codec=Asserting(Lucene94): {}, docValues:{}, maxPointsInLeafNode=1598, maxMBSortInHeap=6.485414969465074, sim=Asserting(RandomSimilarity(queryNorm=true): {}), locale=en-AU, timezone=Europe/Vienna
  2> NOTE: Linux 5.4.0-125-generic amd64/Oracle Corporation 18.0.2.1 (64-bit)/cpus=8,threads=1,free=465272544,total=536870912
  2> NOTE: All tests run in this JVM: [CoordinatorTests]

Tests with failures:
 - org.elasticsearch.cluster.coordination.CoordinatorTests.testSingleNodeDiscoveryStabilisesEvenWhenDisrupted
```


test/framework/src/main/java/org/elasticsearch/cluster/coordination/AbstractCoordinatorTestCase.java
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;
import static org.elasticsearch.transport.TransportService.NOOP_TRANSPORT_INTERCEPTOR;
import static org.elasticsearch.transport.TransportSettings.CONNECT_TIMEOUT;
import static org.hamcrest.Matchers.empty;
import static org.hamcrest.Matchers.equalTo;
import static org.hamcrest.Matchers.greaterThan;
import static org.hamcrest.Matchers.greaterThanOrEqualTo;
import static org.hamcrest.Matchers.hasItem;
import static org.hamcrest.Matchers.is;
import static org.hamcrest.Matchers.lessThanOrEqualTo;
import static org.hamcrest.Matchers.not;
import static org.hamcrest.Matchers.nullValue;
import static org.hamcrest.Matchers.oneOf;
import static org.hamcrest.Matchers.sameInstance;
public class AbstractCoordinatorTestCase extends ESTestCase {