SOLR-18001 fixing the intermittent test failure

[opennj]

https://issues.apache.org/jira/browse/SOLR-18001

Description

LBHttp2SolrClientIntegrationTest > testSimple was FAILED because of java.util.concurrent.TimeoutException. Test was failing intermittently due to Jetty shutdown timeouts and timing issues with load balancer server detection.

Solution

Exception handling: Added try-catch blocks around Jetty stop operations
Timing fixes: Added 100ms delays for LB client to detect server state changes
Timeout control: Added 5-second timeout wrapper for Jetty shutdown
Robust cleanup: Enhanced tearDown methods to log exceptions without failing tests

Tests

Please describe the tests you've developed or run to confirm this patch implements the feature or solves the problem.

Checklist

Please review the following and check all that apply:

• I have reviewed the guidelines for How to Contribute and my code conforms to the standards described there to the best of my ability.
• I have created a Jira issue and added the issue ID to my pull request title.
• I have given Solr maintainers access to contribute to my PR branch. (optional but recommended, not available for branches on forks living under an organisation)
• I have developed this patch against the main branch.
• I have run ./gradlew check.
• I have added tests for my changes.
• I have added documentation for the Reference Guide
• I have added a changelog entry for my change