org.jboss.modules.Metrics causes too-early init of JUL in some JDKs

The org.jboss.modules.Metrics class uselessly references the platform thread MXBean, causing that class to be initialized before classes are loaded (but not actually using it). On some JVMs this causes JUL to be initialized prematurely, which in turn prevents application start (including WildFly).

The best fix is to remove this unused reference completely.