[TESTS] Disable specific locales for RestrictedTrustManagerTest (#33299)

Disable specific Thai and Japanese locales as Certificate expiration
validation fails due to the date parsing of BouncyCastle (that manifests
in a FIPS 140 JVM as this is the only place we use BouncyCastle).
Added the locale switching logic here instead of subclassing
ESTestCase as these are the only tests that fail for these locales and
JVM combination.

Resolves #33081

x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/ssl/RestrictedTrustManagerTests.java

@@ -5,12 +5,17 @@
  */
 package org.elasticsearch.xpack.core.ssl;
 
+import org.apache.logging.log4j.Logger;
+import org.elasticsearch.common.logging.Loggers;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.test.ESTestCase;
 import org.hamcrest.Description;
 import org.hamcrest.TypeSafeMatcher;
+import org.junit.AfterClass;
 import org.junit.Assert;
 import org.junit.Before;
+import org.junit.BeforeClass;
+
 import javax.net.ssl.X509ExtendedTrustManager;
 
 import java.io.IOException;
@@ -28,6 +33,7 @@ import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Objects;
 import java.util.regex.Pattern;
@@ -40,6 +46,34 @@ public class RestrictedTrustManagerTests extends ESTestCase {
     private int numberOfClusters;
     private int numberOfNodes;
 
+    private static Locale restoreLocale;
+
+    @BeforeClass
+    public static void ensureSupportedLocale() throws Exception {
+        Logger logger = Loggers.getLogger(RestrictedTrustManagerTests.class);
+        if (isUnusableLocale()) {
+            // See: https://github.com/elastic/elasticsearch/issues/33081
+            logger.warn("Attempting to run RestrictedTrustManagerTests tests in an unusable locale in a FIPS JVM. Certificate expiration " +
+                "validation will fail, switching to English");
+            restoreLocale = Locale.getDefault();
+            Locale.setDefault(Locale.ENGLISH);
+        }
+    }
+
+    private static boolean isUnusableLocale() {
+        return inFipsJvm() && (Locale.getDefault().toLanguageTag().equals("th-TH")
+            || Locale.getDefault().toLanguageTag().equals("ja-JP-u-ca-japanese-x-lvariant-JP")
+            || Locale.getDefault().toLanguageTag().equals("th-TH-u-nu-thai-x-lvariant-TH"));
+    }
+
+    @AfterClass
+    public static void restoreLocale() throws Exception {
+        if (restoreLocale != null) {
+            Locale.setDefault(restoreLocale);
+            restoreLocale = null;
+        }
+    }
+
     @Before
     public void readCertificates() throws GeneralSecurityException, IOException {