Revert "fix: kill ES container immediately in testStopESContainer to prevent graceful-shutdown race"

This reverts commit ff3e55e.

Author: yeikel

src/test/java/io/confluent/connect/elasticsearch/integration/ElasticsearchConnectorIT.java

@@ -202,14 +202,8 @@ public void testStopESContainer() throws Exception {
     // run connector and write
     runSimpleTest(props);
 
-    // Kill ES immediately (SIGKILL, timeout=0) so it cannot process any more requests.
-    // container.stop() sends SIGTERM and returns before ES dies — ES takes up to 10s
-    // to gracefully shut down, during which bulk requests still succeed and no error
-    // is set. Using withTimeout(0) forces Docker to send SIGKILL immediately.
-    container.getDockerClient()
-        .stopContainerCmd(container.getContainerId())
-        .withTimeout(0)
-        .exec();
+    // stop ES, for all following requests to fail with "connection refused"
+    container.stop();
 
     // try to write some more
     writeRecords(NUM_RECORDS);