Rename some tests from IT to Tests (elastic/elasticsearch#4106)

If these tests were in `:core` then then `IT` would be an appropriate
suffix, but in xplugins they should have `Tests`. This moves them
from the `integTest` task to the `test` task which is a good idea
because it lets them run in parallel with the other tests. Naming
them `IT` means that they are run not in parallel and they are run
with a running instance of Elasticsearch which they don't need.

This cuts the build from 15.5 minutes to 13.5 minutes for me.

Original commit: elastic/x-pack-elasticsearch@7b4bcf8bc5

elasticsearch/src/test/java/org/elasticsearch/OldSecurityIndexBackwardsCompatibilityTests.java

@@ -70,7 +70,7 @@ import static org.hamcrest.Matchers.hasSize;
  *  <li>This document in {@code index3}: {@code {"title": "bwc_test_user should not see this index"}}</li>
  * </ul>
  **/
-public class OldSecurityIndexBackwardsCompatibilityIT extends AbstractOldXPackIndicesBackwardsCompatibilityTestCase {
+public class OldSecurityIndexBackwardsCompatibilityTests extends AbstractOldXPackIndicesBackwardsCompatibilityTestCase {
     private static final Version VERSION_5_1_0_UNRELEASED = Version.fromString("5.1.0");
 
     public void testUnreleasedVersion() {

elasticsearch/src/test/java/org/elasticsearch/integration/ShrinkIndexWithSecurityTests.java

@@ -19,7 +19,7 @@ import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertHitC
  * Integration test that uses multiple data nodes to test that the shrink index api works with security.
  */
 @ClusterScope(minNumDataNodes = 2)
-public class ShrinkIndexWithSecurityIT extends SecurityIntegTestCase {
+public class ShrinkIndexWithSecurityTests extends SecurityIntegTestCase {
 
     @Override
     protected final boolean ignoreExternalCluster() {

elasticsearch/src/test/java/org/elasticsearch/xpack/monitoring/OldMonitoringIndicesBackwardsCompatibilityTests.java

@@ -48,7 +48,7 @@ import static org.hamcrest.Matchers.hasKey;
  */
 //Give ourselves 30 seconds instead o 5 to shut down. Sometimes it takes a while, especially on weak hardware. But we do get there.
 @ThreadLeakLingering(linger = 30000)
-public class OldMonitoringIndicesBackwardsCompatibilityIT extends AbstractOldXPackIndicesBackwardsCompatibilityTestCase {
+public class OldMonitoringIndicesBackwardsCompatibilityTests extends AbstractOldXPackIndicesBackwardsCompatibilityTestCase {
     private final boolean httpExporter = randomBoolean();
 
     @Override

elasticsearch/src/test/java/org/elasticsearch/xpack/watcher/OldWatcherIndicesBackwardsCompatibilityTests.java

@@ -32,7 +32,7 @@ import static org.hamcrest.Matchers.not;
 /**
  * Tests for watcher indexes created before 5.0.
  */
-public class OldWatcherIndicesBackwardsCompatibilityIT extends AbstractOldXPackIndicesBackwardsCompatibilityTestCase {
+public class OldWatcherIndicesBackwardsCompatibilityTests extends AbstractOldXPackIndicesBackwardsCompatibilityTestCase {
     @Override
     public Settings nodeSettings(int ord) {
         return Settings.builder()