Remove unused feature ElementSetAttributeNodeNS

LayoutTests/fast/css/lang-mapped-to-webkit-locale-dynamic.xhtml

Index: LayoutTests/fast/css/lang-mapped-to-webkit-locale-dynamic.xhtml
diff --git a/LayoutTests/fast/css/lang-mapped-to-webkit-locale-dynamic.xhtml b/LayoutTests/fast/css/lang-mapped-to-webkit-locale-dynamic.xhtml
index 3d89d9d8b8135773d4b74be9653c9d19a963a1f6..ca2f68398162c5dde2013e0ec2c4244c89691432 100644
--- a/LayoutTests/fast/css/lang-mapped-to-webkit-locale-dynamic.xhtml
+++ b/LayoutTests/fast/css/lang-mapped-to-webkit-locale-dynamic.xhtml
@@ -34,7 +34,7 @@ function runTest() {
     // The "lang" attribute in the XML namespace should affect locale (since this is an XHTML document).
     var attr1 = document.createAttributeNS("http://www.w3.org/XML/1998/namespace", "xml:lang");
     attr1.value = "zh";
-    x2.setAttributeNodeNS(attr1);
+    x2.setAttributeNode(attr1);
     shouldBeEqualToString("localeOfNode('x2')", "zh");
 
     x2.removeAttributeNode(attr1);
@@ -43,7 +43,7 @@ function runTest() {
     // An attribute with local name "lang" not in the XML namespace should not affect locale.
     var attr2 = document.createAttributeNS("foobar", "fb:lang");
     attr2.value = "ph";
-    x2.setAttributeNodeNS(attr2);
+    x2.setAttributeNode(attr2);
     shouldBeEqualToString("localeOfNode('x2')", "ja");
 
     // If we include js-test-post.js directly, the "TEST COMPLETE" output comes out of order.