Use Strings#EMPTY_ARRAY (#79452)

Trivial follow-up to #79351 that introduced some spots that create fresh
empty string arrays.

Author: DaveCTurner

server/src/test/java/org/elasticsearch/action/admin/cluster/health/ClusterHealthResponsesTests.java

@@ -15,6 +15,7 @@
 import org.elasticsearch.cluster.health.ClusterIndexHealthTests;
 import org.elasticsearch.cluster.health.ClusterStateHealth;
 import org.elasticsearch.cluster.metadata.Metadata;
+import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.io.stream.BytesStreamOutput;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.Writeable;
@@ -43,7 +44,7 @@ public class ClusterHealthResponsesTests extends AbstractSerializingTestCase<Clu
     private final ClusterHealthRequest.Level level = randomFrom(ClusterHealthRequest.Level.values());
 
     public void testIsTimeout() {
-        ClusterHealthResponse res = new ClusterHealthResponse("", new String[]{}, ClusterState.EMPTY_STATE, false);
+        ClusterHealthResponse res = new ClusterHealthResponse("", Strings.EMPTY_ARRAY, ClusterState.EMPTY_STATE, false);
         for (int i = 0; i < 5; i++) {
             res.setTimedOut(randomBoolean());
             if (res.isTimedOut()) {
@@ -56,7 +57,7 @@ public void testIsTimeout() {
     }
 
     public void testTimeoutReturns200IfOptedIn() {
-        ClusterHealthResponse res = new ClusterHealthResponse("", new String[]{}, ClusterState.EMPTY_STATE, true);
+        ClusterHealthResponse res = new ClusterHealthResponse("", Strings.EMPTY_ARRAY, ClusterState.EMPTY_STATE, true);
         for (int i = 0; i < 5; i++) {
             res.setTimedOut(randomBoolean());
             assertEquals(RestStatus.OK, res.status());

x-pack/plugin/transform/src/test/java/org/elasticsearch/xpack/transform/persistence/TransformInternalIndexTests.java

@@ -190,7 +190,7 @@ public void testCreateLatestVersionedIndexIfRequired_GivenShardInitializationPen
         doAnswer(invocationOnMock -> {
             @SuppressWarnings("unchecked")
             ActionListener<ClusterHealthResponse> listener = (ActionListener<ClusterHealthResponse>) invocationOnMock.getArguments()[1];
-            listener.onResponse(new ClusterHealthResponse("", new String[]{}, ClusterState.EMPTY_STATE, false));
+            listener.onResponse(new ClusterHealthResponse("", Strings.EMPTY_ARRAY, ClusterState.EMPTY_STATE, false));
             return null;
         }).when(clusterClient).health(any(), any());
 
@@ -274,7 +274,7 @@ public void testCreateLatestVersionedIndexIfRequired_GivenConcurrentCreationShar
         doAnswer(invocationOnMock -> {
             @SuppressWarnings("unchecked")
             ActionListener<ClusterHealthResponse> listener = (ActionListener<ClusterHealthResponse>) invocationOnMock.getArguments()[1];
-            listener.onResponse(new ClusterHealthResponse("", new String[]{}, ClusterState.EMPTY_STATE, false));
+            listener.onResponse(new ClusterHealthResponse("", Strings.EMPTY_ARRAY, ClusterState.EMPTY_STATE, false));
             return null;
         }).when(clusterClient).health(any(), any());