The LRA coordinator maven module defines the arq profile which loads the arquillian classes to test classpath. But the Arquillian is not used for testing in coordinator module at all.
https://github.com/jbosstm/narayana/blob/5.12.1.Final/rts/lra/coordinator/pom.xml#L155

It would be good to remove the arqullian profile when Arquillian is not used. It's good not to add the Arquillian to classpath when it's not used as Arquillian may bring unexpected dependencies.