We use simply the current test-runtime-classpath as an auxclasspath. That's why we need to add additional test dependencies, that we don't really use, just so that we have them available for the rule tests.

We could improve this by using the m-dependency-p to fetch the needed dependencies into a special folder ./target/rule-test-libs/ and use that as auxclasspath in RuleTst.

Originally posted by @oowekyala in #2629