Summary:

Add an option to generate XML test cases. This PR revives #1181.

Checklist:

• The PR addresses a single issue. If it can be divided into multiple independent PRs, please do so.
• The PR is divided into a logical sequence of commits OR a single commit is sufficient.
• There are no unnecessary commits (e.g. commits fixing issues in a previous commit in the same PR).
• Each commit has a meaningful message documenting what it does.
• All messages added to the codebase, all comments, as well as commit messages are spellchecked.
• The code is commented OR not applicable/necessary.
• The patch is formatted via clang-format OR not applicable (if explicitly overridden leave unchecked and explain).
• There are test cases for the code you added or modified OR no such test cases are required.