Run parallel tests on ci.jenkins.io

[MarkEWaite]

Run parallel tests on ci.jenkins.io

Parallel tests consistently run faster for this repository than running the tests in a single Java virtual machine. Use a Java virtual machine per core when running on ci.jenkins.io.

What has been done

1. Confirmed with multiple test runs on ci.jenkins.io (using Pipeline replay) that forkCount: '1C' consistently completes tests faster then the default setting

How to test

1. Run with mvn clean -DforkCount=1C verify

Checklist

• Git commits follow best practices
• Build passes in Jenkins
• Appropriate tests or explanation to why this change has no tests
• Pull Request is marked with appropriate label (see .github/release-drafter.yml)
• JIRA issue is well described (problem explanation, steps to reproduce, screenshots)
• For dependency updates: links to external changelogs and, if possible, full diffs