Fix wxXmlNode self-assignment.

Don't lose the node contents if it's assigned to itself.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@73992 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Re-enable a single m_anyDoubleDouble1 test in wxAny test case.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@73993 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775