It looks like this suite timed out because a node of the backing cluster exploded. Looks like an assertion was tripped.

```
» [2023-10-09T21:16:07,555][ERROR][o.e.b.ElasticsearchUncaughtExceptionHandler] [v8.8.2-2] fatal error in thread [elasticsearch[v8.8.2-2][clusterApplierService#updateTask][T#1]], exiting java.lang.AssertionError: provided source [{"_doc":{"_data_stream_timestamp":{"enabled":true},"_source":{"mode":"synthetic"},"properties":{"@timestamp":{"type":"date"},"key":{"type":"keyword","time_series_dimension":true}}}}] differs from mapping [{"_doc":{"_data_stream_timestamp":{"enabled":true},"properties":{"@timestamp":{"type":"date"},"key":{"type":"keyword","time_series_dimension":true}}}}]
»  	at org.elasticsearch.server@8.8.2/org.elasticsearch.index.mapper.DocumentMapper.<init>(DocumentMapper.java:42)
»  	at org.elasticsearch.server@8.8.2/org.elasticsearch.index.mapper.MapperService.newDocumentMapper(MapperService.java:376)
»  	at org.elasticsearch.server@8.8.2/org.elasticsearch.index.mapper.MapperService.updateMapping(MapperService.java:285)
»  	at org.elasticsearch.server@8.8.2/org.elasticsearch.index.IndexService.updateMapping(IndexService.java:700)
»  	at org.elasticsearch.server@8.8.2/org.elasticsearch.indices.cluster.IndicesClusterStateService.createIndicesAndUpdateShards(IndicesClusterStateService.java:493)
»  	at org.elasticsearch.server@8.8.2/org.elasticsearch.indices.cluster.IndicesClusterStateService.applyClusterState(IndicesClusterStateService.java:250)
»  	at org.elasticsearch.server@8.8.2/org.elasticsearch.cluster.service.ClusterApplierService.callClusterStateAppliers(ClusterApplierService.java:536)
»  	at org.elasticsearch.server@8.8.2/org.elasticsearch.cluster.service.ClusterApplierService.callClusterStateAppliers(ClusterApplierService.java:522)
»  	at org.elasticsearch.server@8.8.2/org.elasticsearch.cluster.service.ClusterApplierService.applyChanges(ClusterApplierService.java:495)
»  	at org.elasticsearch.server@8.8.2/org.elasticsearch.cluster.service.ClusterApplierService.runTask(ClusterApplierService.java:426)
»  	at org.elasticsearch.server@8.8.2/org.elasticsearch.cluster.service.ClusterApplierService$UpdateTask.run(ClusterApplierService.java:154)
»  	at org.elasticsearch.server@8.8.2/org.elasticsearch.common.util.concurrent.ThreadContext$ContextPreservingRunnable.run(ThreadContext.java:916)
»  	at org.elasticsearch.server@8.8.2/org.elasticsearch.common.util.concurrent.PrioritizedEsThreadPoolExecutor$TieBreakingPrioritizedRunnable.runAndClean(PrioritizedEsThreadPoolExecutor.java:217)
»  	at org.elasticsearch.server@8.8.2/org.elasticsearch.common.util.concurrent.PrioritizedEsThreadPoolExecutor$TieBreakingPrioritizedRunnable.run(PrioritizedEsThreadPoolExecutor.java:183)
»  	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
»  	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
»  	at java.base/java.lang.Thread.run(Thread.java:1623)
»  
»  
»  ERROR: Elasticsearch exited unexpectedly
```

**Build scan:**
https://gradle-enterprise.elastic.co/s/bte5oskoqsjl6/tests/:qa:mixed-cluster:v8.8.2%23mixedClusterTest/org.elasticsearch.backwards.MixedClusterClientYamlTestSuiteIT
**Reproduction line:**
```
null
```

**Applicable branches:**
main

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

**Failure history:**
https://gradle-enterprise.elastic.co/scans/tests?tests.container=org.elasticsearch.backwards.MixedClusterClientYamlTestSuiteIT&tests.test=classMethod
**Failure excerpt:**
```
java.lang.Exception: Suite timeout exceeded (>= 2400000 msec).

  at __randomizedtesting.SeedInfo.seed([E230389699262455]:0)

```
server/src/test/java/org/elasticsearch/index/query/SearchExecutionContextTests.java
clusterAlias,
            null,
            () -> true,
            null,
            runtimeMappings
        );
    }
    private static MapperService createMapperService(IndexSettings indexSettings, MappingLookup mappingLookup) {
        IndexAnalyzers indexAnalyzers = IndexAnalyzers.of(singletonMap("default", new NamedAnalyzer("default", AnalyzerScope.INDEX, null)));
        IndicesModule indicesModule = new IndicesModule(Collections.emptyList());
        MapperRegistry mapperRegistry = indicesModule.getMapperRegistry();
        Supplier<SearchExecutionContext> searchExecutionContextSupplier = () -> { throw new UnsupportedOperationException(); };
        MapperService mapperService = mock(MapperService.class);
        when(mapperService.getIndexAnalyzers()).thenReturn(indexAnalyzers);
        when(mapperService.parserContext()).thenReturn(
            new MappingParserContext(
                null,
                type -> mapperRegistry.getMapperParser(type, indexSettings.getIndexVersionCreated()),
                mapperRegistry.getRuntimeFieldParsers()::get,
                indexSettings.getIndexVersionCreated(),
                () -> TransportVersion.current(),
                searchExecutionContextSupplier,
                ScriptCompiler.NONE,
                indexAnalyzers,
                indexSettings,
                indexSettings.getMode().buildIdFieldMapper(() -> true)
            )
        );
        when(mapperService.isMultiField(anyString())).then(
            (Answer<Boolean>) invocation -> mappingLookup.isMultiField(invocation.getArgument(0))