Fix test issue where index is explicitly deleted during cluster state update

Calling indicesService.deleteIndex() can trip an assertion if there is an ongoing cluster state applied in
IndicesClusterStateService. This means that the index is possibly deleted after the failMissingShards
check and before we try creating new and updated shards, tripping an assertion that non-existing shards must
have shard state initializing (started in this case).

core/src/test/java/org/elasticsearch/indices/IndicesServiceTests.java

@@ -285,9 +285,6 @@ public class IndicesServiceTests extends ESSingleNodeTestCase {
         listener.latch.await();
         assertThat(clusterService.state(), not(originalState));
         assertNotNull(clusterService.state().getMetaData().index(alias));
-
-        // cleanup
-        indicesService.deleteIndex(test.index(), "finished with test");
     }
 
     /**