Use of XPath queries contain wild cards that fetch an attribute

[CR #331064] The xmlextract and xmltest built-in functions return incorrect results for an XPath query that specifies an attribute reference to the right of a wild card and an element reference.

For example, the following should return “99,” but instead returns an empty result:

select xmlextract("/a/*/c/@at", "<a><b> <c at='99'/></b></a>")

Workaround: Specify a descendant-path query:

select xmlextract("/a/*//c/@at", "<a><b> <c at='99'/></b></a>")