Mute MlDistributedFailureIT#testFullClusterRestart()

Relates elastic/elasticsearch#25415

Original commit: elastic/x-pack-elasticsearch@01fa0e7601

plugin/src/test/java/org/elasticsearch/xpack/ml/integration/MlDistributedFailureIT.java

@@ -88,6 +88,7 @@ public class MlDistributedFailureIT extends BaseMlIntegTestCase {
         });
     }
 
+    @AwaitsFix(bugUrl = "https://github.com/elastic/elasticsearch/issues/25415")
     public void testFullClusterRestart() throws Exception {
         internalCluster().ensureAtLeastNumDataNodes(3);
         ensureStableClusterOnAllNodes(3);