Discovered with the help of https://github.com/belingueres/xml-conformance

MXParser fails on parts of the W3C XML Conformance Test Suite.

In this issue, it is failing ibm32n01.xml and ibm32n09.xml from "IBM XML Conformance Test Suite - Production 32" (see https://github.com/belingueres/xml-conformance/blob/main/src/test/resources/xmlconf/ibm/ibm_oasis_not-wf.xml) regarding the xml declaration of the xml file as 'standalone'.