Drop unused @ThirdParty tests (#118432)

We don't run any such tests in CI, and probably haven't even run them
manually for years. The only such test with this annotation is a trivial
smoke test for `discovery-ec2` that is equally well covered by the Java
REST test suite.

Author: DaveCTurner

plugins/discovery-ec2/build.gradle

@@ -6,7 +6,6 @@
  * your election, the "Elastic License 2.0", the "GNU Affero General Public
  * License v3.0 only", or the "Server Side Public License, v 1".
  */
-apply plugin: 'elasticsearch.internal-cluster-test'
 apply plugin: 'elasticsearch.internal-java-rest-test'
 
 esplugin {

plugins/discovery-ec2/src/internalClusterTest/java/org/elasticsearch/discovery/ec2/AbstractAwsTestCase.java

@@ -13,7 +13,6 @@
 import io.netty.util.concurrent.GlobalEventExecutor;
 
 import com.carrotsearch.randomizedtesting.RandomizedContext;
-import com.carrotsearch.randomizedtesting.annotations.TestGroup;
 import com.carrotsearch.randomizedtesting.generators.RandomNumbers;
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
 
@@ -273,26 +272,6 @@
 @LuceneTestCase.SuppressFileSystems("ExtrasFS") // doesn't work with potential multi data path from test cluster yet
 public abstract class ESIntegTestCase extends ESTestCase {
 
-    /**
-     * Property that controls whether ThirdParty Integration tests are run (not the default).
-     */
-    public static final String SYSPROP_THIRDPARTY = "tests.thirdparty";
-
-    /**
-     * Annotation for third-party integration tests.
-     * <p>
-     * These are tests, which require a third-party service in order to run. They
-     * may require the user to manually configure an external process (such as rabbitmq),
-     * or may additionally require some external configuration (e.g. AWS credentials)
-     * via the {@code tests.config} system property.
-     */
-    @Inherited
-    @Retention(RetentionPolicy.RUNTIME)
-    @Target(ElementType.TYPE)
-    @TestGroup(enabled = false, sysProperty = ESIntegTestCase.SYSPROP_THIRDPARTY)
-    public @interface ThirdParty {
-    }
-
     /** node names of the corresponding clusters will start with these prefixes */
     public static final String SUITE_CLUSTER_NODE_PREFIX = "node_s";
     public static final String TEST_CLUSTER_NODE_PREFIX = "node_t";