test: update behavior of namespaces in HTML4

libxml 2.11.0 fixes the parser to ignore the namespaces as a
namespace, but not to split the QName (see upstream commit d7d0bc65).

Fixes #2836

test/xml/test_node.rb

@@ -1141,17 +1141,17 @@ def test_namespace_without_an_href_on_html_node
           node = html.at("div").children.first
           refute_nil(node)
 
-          if Nokogiri.uses_libxml?(">= 2.9.12")
+          if Nokogiri.uses_libxml?(">= 2.11.0") || Nokogiri.jruby?
+            assert_empty(node.namespaces.keys)
+            assert_equal("<o:p>foo</o:p>", node.to_html)
+          elsif Nokogiri.uses_libxml?(">= 2.9.12")
             assert_empty(node.namespaces.keys)
             assert_equal("<p>foo</p>", node.to_html)
           elsif Nokogiri.uses_libxml?
             assert_equal(1, node.namespaces.keys.size)
             assert(node.namespaces.key?("xmlns:o"))
             assert_nil(node.namespaces["xmlns:o"])
             assert_equal("<p>foo</p>", node.to_html)
-          else # jruby
-            assert_empty(node.namespaces.keys)
-            assert_equal("<o:p>foo</o:p>", node.to_html)
           end
         end