Flaky-test: BasicEndToEndTest. testRegexTopicsWithInitialPosition

BasicEndToEndTest. testRegexTopicsWithInitialPosition is flaky. It fails sporadically.

[example failure](https://github.com/apache/pulsar/runs/6588959111?check_suite_focus=true)

```
[ RUN ] BasicEndToEndTest.testRegexTopicsWithInitialPosition
2022-05-25 11:29:05.841 INFO [140692561309376] ClientConnection:189 | [ -> pulsar://localhost:6650] Create ClientConnection, timeout=10000
2022-05-25 11:29:05.841 INFO [140692561309376] ConnectionPool:96 | Created connection for pulsar://localhost:6650
2022-05-25 11:29:05.842 INFO [140692558206720] ClientConnection:375 | [127.0.0.1:43072 -> 127.0.0.1:6650] Connected to broker
2022-05-25 11:29:05.843 INFO [140692558206720] HandlerBase:64 | [persistent://public/default/test-regex-initial-position-[165](https://github.com/apache/pulsar/runs/6588959111?check_suite_focus=true#step:11:166)3478145, ] Getting connection from pool
2022-05-25 11:29:05.845 INFO [140692558206720] ProducerImpl:189 | [persistent://public/default/test-regex-initial-position-1653478145, ] Created producer on broker [127.0.0.1:43072 -> 127.0.0.1:6650]
2022-05-25 11:29:05.850 INFO [140692558206720] HandlerBase:64 | [persistent://public/default/test-regex-initial-position-1653478145, testRegexTopicsWithMessageListener-sub, 0] Getting connection from pool
2022-05-25 11:29:05.854 INFO [140692558206720] ConsumerImpl:224 | [persistent://public/default/test-regex-initial-position-1653478145, testRegexTopicsWithMessageListener-sub, 0] Created consumer on broker [127.0.0.1:43072 -> 127.0.0.1:6650]
2022-05-25 11:29:05.854 INFO [140692558206720] MultiTopicsConsumerImpl:95 | Successfully Subscribed to Topics
2022-05-25 11:29:05.859 INFO [140692561309376] ClientImpl:499 | Closing Pulsar client with 1 producers and 1 consumers
2022-05-25 11:29:05.859 INFO [140692561309376] ProducerImpl:665 | [persistent://public/default/test-regex-initial-position-1653478145, standalone-0-154] Closing producer for topic persistent://public/default/test-regex-initial-position-1653478145
2022-05-25 11:29:05.859 INFO [140692561309376] ProducerImpl:708 | [persistent://public/default/test-regex-initial-position-1653478145, standalone-0-154] Closed producer
2022-05-25 11:29:05.859 INFO [140692561309376] ConsumerImpl:1005 | [persistent://public/default/test-regex-initial-position-1653478145, testRegexTopicsWithMessageListener-sub, 0] Closing consumer for topic persistent://public/default/test-regex-initial-position-1653478145
2022-05-25 11:29:05.859 INFO [140692561309376] ConsumerImpl:1062 | [persistent://public/default/test-regex-initial-position-1653478145, testRegexTopicsWithMessageListener-sub, 0] Closed consumer 0
[93/295] BasicEndToEndTest.testRegexTopicsWithInitialPosition returned/aborted with exit code -11 (289 ms)
```

Start with the linked GitHub Actions failure and locate BasicEndToEndTest.testRegexTopicsWithInitialPosition in the repository. Reproduce the sporadic failure and inspect the available test output around the connection, subscription, and exit-code -11 messages. Done means the intermittent failure is understood and the test is reliable.

Written by the indexing model from the issue text.