Refactor org.jboss.as.jpa.transaction.TransactionUtil to not use static globals, use the JPAService singleton instead

   public static TransactionManager getTransactionManager() {
     JPAService jpaService = 
currentServiceContainer().getService(org.jboss.as.jpa.service.JPAService.SERVICE_NAME);
   return jpaService.getTransactionManager();
   }
    private static ServiceContainer currentServiceContainer() {
        if(System.getSecurityManager() == null) {
            return CurrentServiceContainer.getServiceContainer();
        }
        return AccessController.doPrivileged(CurrentServiceContainer.GET_ACTION);
    }