Fix issues related to new semantics of XML namspacing in Chrome

[Michael Aufreiter]

As reported by Danne from Infomaker:

It seems the problem stems from version 61.0.3163.79 of Chrome. This change
in testing code accurately describes the previous behaviour and the new behaviour:
https://chromium.googlesource.com/chromium/src/+/758742204e186ac83e73b4a393bdfaa660e2ca15%5E%21/#F0

The relevant section in the W3C Namespaces recommendation
https://www.w3.org/TR/xml-names/#defaulting