Allow grouping results by the "testsuite" tag

### What feature do you want to see added?

Currently, JUnit allows the result grouping based on the step name in the pipeline.
However for various reasons people might not use pipelines and still want to group testcases (in my case, a few pytest runs with different parameters happen). Fortunately, xml results contain a tag that could be used for result grouping, as one can see in the first lines of the xml report:

for pytest, the testsuite name is defined by the option `junit_suite_name`, I'm sure other environments allow this in the similar manner.

### Upstream changes

_No response_