Support multiple system-out tags per testcase

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

JUnit 5 can output multiple system-out (and system-err) tags per testcase tag.
It would be useful if the plugin would pick up the contents of all system-out tags as part of the testcase's stdout contents.

e.g.:
https://stackoverflow.com/questions/53822338/jenkins-not-displaying-test-case-stdout

### Upstream changes

_No response_

### Are you interested in contributing this feature?

_No response_