In WFLY-4392 a property named enableThreadContextClassLoader was added to the jmx-as7 protocol. When set to false the ClassLoader.getSystemClassLoader() is used as the class loader. This doesn't work with JUnit 5 because the TestEngine is looked up via a service loader and the implementation is not on the boot class loader.

We may just need to throw an exception explaining the issue if JUnit 5 is detected for this protocol and the feature is enabled.