Changed JUnit XML result generator

[martingrossmann]

Description

The old JUnit XML result generator ignored skipped tests and did not handle retried tests. Furthermore the old generator based on and old version of Maven Surefire Plugin (https://github.com/apache/maven-surefire/tree/b9b2381a3dba6574bb69bd91d45fe0edea29c779/surefire-api/src/main/java/org/apache/maven/surefire/api/report).

TestNG has an own JUnitXmlReporter listener (https://github.com/cbeust/testng/blob/master/testng-core/src/main/java/org/testng/reporters/JUnitXMLReporter.java). The TestNG implemenation was migrated to Testerra event system.

Fixes # (issue)

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules