Add mysqltest-case for 442bp2_xml_feature branch

Description

This is a request to add a mysqltest case for the feature branch 442bp2_xml_feature. The target branch for this work is master.

Environment

• Target Branch: master < 442bp2_xml_feature
• Is this an RD-provided temporary version? No
• Reproducibility: Not specified
• Test Changes: Not specified
• Other environmental anomalies or changes: Not specified
• Environment Information: Not specified
• Log Information: Not provided

Steps to Reproduce / Scenario Description

Not provided. Please describe the workload run on the environment, actions taken before the issue occurred, and any test changes.

Note: Strongly discouraged to only post ERROR logs or stack traces without context.

Other Information

For issues reported from external business operations, please correctly select the "Work Item Type" based on the actual situation:

• Customer Service Feedback: Specifically refers to issues before production deployment or during POC, where a product bug is confirmed and requires a fix and release.
• Online Issue: An issue that has occurred in a production environment, confirmed as a product bug, but not classified as a fault.
• Online Fault: An issue that has occurred in a production environment, confirmed as a product bug, causing business errors or public impact on the customer side (the authority to define a fault belongs to the delivery service team).

Start by locating existing mysqltest cases covering XML features and compare how they are organized for the master branch. Determine the expected behavior for the 442bp2_xml_feature branch, then add a test that exercises that workload and passes with the feature integrated into master.