[Test] Wait for expected master on all nodes (#131399)

This PR changes the test to simply wait expected master on every node
instead of selectively waiting on one non-master and one master node.
The later is problematic since it uses API that is not suitable when the
cluster is changing master.

Relates: #127213

Author: ywangd

server/src/internalClusterTest/java/org/elasticsearch/cluster/SpecificMasterNodesIT.java

@@ -60,26 +60,30 @@ public void testElectOnlyBetweenMasterNodes() throws Exception {
 
         logger.info("--> start master node (1)");
         final String masterNodeName = internalCluster().startMasterOnlyNode();
-        awaitMasterNode(internalCluster().getNonMasterNodeName(), masterNodeName);
-        awaitMasterNode(internalCluster().getMasterName(), masterNodeName);
+        for (var nodeName : internalCluster().getNodeNames()) {
+            awaitMasterNode(nodeName, masterNodeName);
+        }
 
         logger.info("--> start master node (2)");
         final String nextMasterEligableNodeName = internalCluster().startMasterOnlyNode();
-        awaitMasterNode(internalCluster().getNonMasterNodeName(), masterNodeName);
-        awaitMasterNode(internalCluster().getMasterName(), masterNodeName);
+        for (var nodeName : internalCluster().getNodeNames()) {
+            awaitMasterNode(nodeName, masterNodeName);
+        }
 
         logger.info("--> closing master node (1)");
         client().execute(
             TransportAddVotingConfigExclusionsAction.TYPE,
             new AddVotingConfigExclusionsRequest(TEST_REQUEST_TIMEOUT, masterNodeName)
         ).get();
         // removing the master from the voting configuration immediately triggers the master to step down
-        awaitMasterNode(internalCluster().getNonMasterNodeName(), nextMasterEligableNodeName);
-        awaitMasterNode(internalCluster().getMasterName(), nextMasterEligableNodeName);
+        for (var nodeName : internalCluster().getNodeNames()) {
+            awaitMasterNode(nodeName, nextMasterEligableNodeName);
+        }
 
         internalCluster().stopNode(masterNodeName);
-        awaitMasterNode(internalCluster().getNonMasterNodeName(), nextMasterEligableNodeName);
-        awaitMasterNode(internalCluster().getMasterName(), nextMasterEligableNodeName);
+        for (var nodeName : internalCluster().getNodeNames()) {
+            awaitMasterNode(nodeName, nextMasterEligableNodeName);
+        }
     }
 
     public void testAliasFilterValidation() {