The News page is defined in the jboss-portal.sar/conf/data/default-object.xml file. In the source, you can find it at ./core/src/resources/portal-core-sar/conf/data/default-object.xml.
The Test page is defined in the jboss-portal.sar/portal-samples.war/WEB-INF/default-object.xml file. In the source you can find it at ./core/src/resources/portal-samples-war/WEB-INF/default-object.xml
Edit those files to remove the News and Test pages, and they should no longer show up when you recompile and deploy the portal.