build: xml-light is no longer required (thanks Maxim Koltsov).

build: xml-light is no longer required (thanks Maxim Koltsov).

At some point we removed the last thing that required
xml-light, but were still testing for it at various places
in the build.  This removes all traces.
(cherry picked from commit f6c4026f85fa6ded33a51ec2757abda9f116fd5f)