Make arguments to Element methods non-optional

LayoutTests/fast/dom/Element/script-tests/setAttributeNS-namespace-err.js

 description("setAttributeNS tests adapted from createAttributeNS which in turn were adapted from createElementNS tests attached to webkit bug 16833");
 
 function assert(c, m)
 {
     if (!c)
         testFailed(m);
     else
         testPassed(m);
 }
 
@@ skipping 106 matching lines @@
             msg += "; " + test.message;
         try {
             setFunction.apply(element, test.args.concat([value]));
             assert(!("code" in test), msg);
         } catch (e) {
             assertEquals(e.code, test.code || "expected no exception", msg);
         }
     }
 }
 
-// Moz throws a "Not enough arguments" exception in these, we don't:
-var element = document.createElement("div");
-shouldBeUndefined("element.setAttributeNS()");
-shouldBeUndefined("element.setAttributeNS(\"http://www.example.com\")");
-shouldBeUndefined("element.setAttributeNS(\"http://www.example.com\", \"foo\")");
-
 runNSTests();