[TEST] Work around race condition when starting clusters in parallel (#118145)

With #117820 we are starting clusters in parallel in CCS related tests.

There is a race condition when calling RandomizedTest#isNightly, which
is called as part of `InternalTestCluster#beforeTest`.

See randomizedtesting/randomizedtesting#311.
Until this is fixed upstream, we can simply call isNightly before
forking, which is going to trigger the lazy initialization of the inner
map that causes the race. From then on, all threads will have a
consistent view of it.

Closes #118124

Author: javanna

muted-tests.yml

@@ -239,9 +239,6 @@ tests:
 - class: org.elasticsearch.packaging.test.ConfigurationTests
   method: test30SymlinkedDataPath
   issue: https://github.com/elastic/elasticsearch/issues/118111
-- class: org.elasticsearch.datastreams.ResolveClusterDataStreamIT
-  method: testClusterResolveWithDataStreamsUsingAlias
-  issue: https://github.com/elastic/elasticsearch/issues/118124
 - class: org.elasticsearch.packaging.test.KeystoreManagementTests
   method: test30KeystorePasswordFromFile
   issue: https://github.com/elastic/elasticsearch/issues/118123

test/framework/src/main/java/org/elasticsearch/test/AbstractMultiClustersTestCase.java

@@ -9,6 +9,8 @@
 
 package org.elasticsearch.test;
 
+import com.carrotsearch.randomizedtesting.RandomizedTest;
+
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.elasticsearch.action.admin.cluster.remote.RemoteInfoRequest;
@@ -108,6 +110,11 @@ public final void startClusters() throws Exception {
             MockTransportService.TestPlugin.class,
             getTestTransportPlugin()
         );
+        // We are going to initialize multiple clusters concurrently, but there is a race condition around the lazy initialization of test
+        // groups in GroupEvaluator across multiple threads. See https://github.com/randomizedtesting/randomizedtesting/issues/311.
+        // Calling isNightly before parallelizing is enough to work around that issue.
+        @SuppressWarnings("unused")
+        boolean nightly = RandomizedTest.isNightly();
         runInParallel(clusterAliases.size(), i -> {
             String clusterAlias = clusterAliases.get(i);
             final String clusterName = clusterAlias.equals(LOCAL_CLUSTER) ? "main-cluster" : clusterAlias;