Flaky-test: PulsarFunctionsJavaProcessTest.testTumblingCountWindowTest

### Search before reporting

- [x] I searched in the [issues](https://github.com/apache/pulsar/issues) and found nothing similar.

### Example failure

https://github.com/apache/pulsar/actions/runs/18443739797/job/52548413025#step:12:5499

### Exception stacktrace

```text
org.testng.internal.thread.ThreadTimeoutException: Method org.apache.pulsar.tests.integration.functions.java.PulsarFunctionsJavaTest.testTumblingCountWindowTest() didn't finish within the time-out 300000
at java.base/jdk.internal.misc.Unsafe.park(Native Method)
at java.base/java.util.concurrent.locks.LockSupport.park(LockSupport.java:221)
at java.base/java.util.concurrent.CompletableFuture$Signaller.block(CompletableFuture.java:1864)
at java.base/java.util.concurrent.ForkJoinPool.unmanagedBlock(ForkJoinPool.java:3780)
at java.base/java.util.concurrent.ForkJoinPool.managedBlock(ForkJoinPool.java:3725)
at java.base/java.util.concurrent.CompletableFuture.waitingGet(CompletableFuture.java:1898)
at java.base/java.util.concurrent.CompletableFuture.get(CompletableFuture.java:2072)
at org.apache.pulsar.tests.integration.utils.DockerUtils.runCommand(DockerUtils.java:182)
at org.apache.pulsar.tests.integration.containers.ChaosContainer.execCmd(ChaosContainer.java:107)
at org.apache.pulsar.tests.integration.functions.PulsarFunctionsTest.testWindowFunction(PulsarFunctionsTest.java:294)
at org.apache.pulsar.tests.integration.functions.java.PulsarFunctionsJavaTest.testTumblingCountWindowTest(PulsarFunctionsJavaTest.java:204)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
at java.base/java.lang.reflect.Method.invoke(Method.java:580)
at org.testng.internal.invokers.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:139)
at org.testng.internal.invokers.InvokeMethodRunnable.runOne(InvokeMethodRunnable.java:47)
at org.testng.internal.invokers.InvokeMethodRunnable.call(InvokeMethodRunnable.java:76)
at org.testng.internal.invokers.InvokeMethodRunnable.call(InvokeMethodRunnable.java:11)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:317)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
at java.base/java.lang.Thread.run(Thread.java:1583)
```

### Are you willing to submit a PR?

- [ ] I'm willing to submit a PR!

Start with PulsarFunctionsJavaTest.testTumblingCountWindowTest and the shared testWindowFunction path in PulsarFunctionsTest, then inspect DockerUtils.runCommand and ChaosContainer.execCmd from the stack trace. Reproduce the linked CI failure and determine why the test exceeds its 300000 ms timeout; done means the test completes reliably without timing out.

Written by the indexing model from the issue text.