Cleanup after DockerTests suite completes (#54164) (#54646)

Closes #54101. The Docker tests weren't cleanup up the created container
after the last test completed. Now they are.

Co-authored-by: Rory Hunter <pugnascotia@users.noreply.github.com>

qa/os/src/test/java/org/elasticsearch/packaging/test/DockerTests.java

@@ -26,6 +26,7 @@
 import org.elasticsearch.packaging.util.ServerUtils;
 import org.elasticsearch.packaging.util.Shell.Result;
 import org.junit.After;
+import org.junit.AfterClass;
 import org.junit.Before;
 import org.junit.BeforeClass;
 
@@ -46,6 +47,7 @@
 import static org.elasticsearch.packaging.util.Docker.getImageLabels;
 import static org.elasticsearch.packaging.util.Docker.getJson;
 import static org.elasticsearch.packaging.util.Docker.mkDirWithPrivilegeEscalation;
+import static org.elasticsearch.packaging.util.Docker.removeContainer;
 import static org.elasticsearch.packaging.util.Docker.rmDirWithPrivilegeEscalation;
 import static org.elasticsearch.packaging.util.Docker.runContainer;
 import static org.elasticsearch.packaging.util.Docker.runContainerExpectingFailure;
@@ -83,6 +85,11 @@ public static void filterDistros() {
         assumeTrue("only Docker", distribution().isDocker());
     }
 
+    @AfterClass
+    public static void teardownSuite() {
+        removeContainer();
+    }
+
     @Before
     public void setupTest() throws IOException {
         installation = runContainer(distribution());