DanglingIndicesIT should ensure node removed first (#50896)

These tests occasionally failed because the deletion was submitted before the
restarting node was removed from the cluster, causing the deletion not to be
fully acked. This commit fixes this by checking the restarting node has been
removed from the cluster.

Author: DaveCTurner

server/src/test/java/org/elasticsearch/indices/recovery/DanglingIndicesIT.java

@@ -77,6 +77,7 @@ public void testDanglingIndicesAreRecoveredWhenSettingIsEnabled() throws Excepti
 
             @Override
             public Settings onNodeStopped(String nodeName) throws Exception {
+                ensureClusterSizeConsistency();
                 assertAcked(client().admin().indices().prepareDelete(INDEX_NAME));
                 return super.onNodeStopped(nodeName);
             }
@@ -107,6 +108,7 @@ public void testDanglingIndicesAreNotRecoveredWhenSettingIsDisabled() throws Exc
 
             @Override
             public Settings onNodeStopped(String nodeName) throws Exception {
+                ensureClusterSizeConsistency();
                 assertAcked(client().admin().indices().prepareDelete(INDEX_NAME));
                 return super.onNodeStopped(nodeName);
             }
@@ -136,6 +138,7 @@ public void testDanglingIndicesAreNotRecoveredWhenNotWritten() throws Exception
 
             @Override
             public Settings onNodeStopped(String nodeName) throws Exception {
+                ensureClusterSizeConsistency();
                 assertAcked(client().admin().indices().prepareDelete(INDEX_NAME));
                 return super.onNodeStopped(nodeName);
             }