Weld SE does not support empty beans.xml files

Weld SE has a problem while scanning bean archives, if the application has multiple archives with an empty beans.xml. Only the last detected archive is considered.

An empty beans.xml is represented with the constant org.jboss.weld.bootstrap.spi.BeansXml.EMPTY_BEANS_XML. The problem is, that implementations of org.jboss.weld.environment.deployment.discovery.BeansXml use this .EMPTY_BEANS_XML as key in a HashMap, which should contain all discovered bean archives. But because the key for jars with an empty beans.xml is always the same, they are not discovered properly.