The org.jboss.resteasy.microprofile.config module is in WildFly, however it's not exported to deployments. In the RESTEasy galleon pack module the exports this module as an optional module dependency.
Something similar should be done in WildFly. This can be done either via the org.jboss.resteasy.resteasy-core module like in the RESTEasy galleon pack or it needs to be added to deployments via a DUP.
Note too that while doing this the module name should be removed LayersTestCase.NOT_USED_COMMON array as it should be added correctly after this change.