Looks like the watcher thread was interrupted but the interrupt was lost somewhere along the way.

**Build scan:**
https://gradle-enterprise.elastic.co/s/tkibjrfrug5pw/tests/:server:test/org.elasticsearch.reservedstate.service.FileSettingsServiceTests/testStopWorksIfProcessingDidntReturnYet

**Reproduction line:**
```
./gradlew ':server:test' --tests "org.elasticsearch.reservedstate.service.FileSettingsServiceTests.testStopWorksIfProcessingDidntReturnYet" -Dtests.seed=2A90D2A7A2E74E69 -Dtests.locale=sl-SI -Dtests.timezone=America/Fortaleza -Druntime.java=17
```

**Applicable branches:**
8.7

**Reproduces locally?:**
Didn't try

**Failure history:**
https://gradle-enterprise.elastic.co/scans/tests?tests.container=org.elasticsearch.reservedstate.service.FileSettingsServiceTests&tests.test=testStopWorksIfProcessingDidntReturnYet

**Failure excerpt:**
```
java.lang.Exception: Test abandoned because suite timeout was reached.

  at __randomizedtesting.SeedInfo.seed([2A90D2A7A2E74E69]:0)

```
server/src/test/java/org/elasticsearch/reservedstate/service/FileSettingsServiceTests.java
import org.elasticsearch.threadpool.ThreadPool;
import org.elasticsearch.xcontent.XContentParser;
import org.junit.After;
import org.junit.Before;
import org.mockito.Mockito;
import org.mockito.stubbing.Answer;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.StandardCopyOption;
import java.nio.file.StandardWatchEventKinds;
import java.nio.file.WatchKey;
import java.nio.file.attribute.FileTime;
import java.time.Instant;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.ZoneOffset;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.function.Consumer;
import static org.elasticsearch.node.Node.NODE_NAME_SETTING;
import static org.hamcrest.Matchers.sameInstance;
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.ArgumentMatchers.anyInt;
import static org.mockito.ArgumentMatchers.eq;