Have getElementsByClassName() / getElementsByTagName*() return an HTMLCollection

LayoutTests/fast/js/constructor-expected.txt

 This tests the constructor property of DOM objects: http://bugs.webkit.org/show_bug.cgi?id=11315
 
 On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
 
 
 PASS window.document.constructor === window.Object is false
 PASS window.document.constructor === window.HTMLDocument is true
 PASS window.document.constructor.prototype === window.HTMLDocument.prototype is true
 PASS window.document.constructor.prototype.__proto__ === window.HTMLDocument.prototype.__proto__ is true
 PASS window.document.constructor.prototype.__proto__ === window.Document.prototype is true
 PASS window.document.body.constructor === window.HTMLBodyElement is true
 PASS window.document.body.constructor.prototype === window.HTMLBodyElement.prototype is true
 PASS window.document.body.constructor.prototype.__proto__ === window.HTMLBodyElement.prototype.__proto__ is true
 PASS window.document.body.constructor.prototype.__proto__ === window.HTMLElement.prototype is true
-PASS nodeList.constructor === window.NodeList is true
-PASS nodeList.constructor.prototype === window.NodeList.prototype is true
+PASS htmlCollection.constructor === window.HTMLCollection is true
+PASS htmlCollection.constructor.prototype === window.HTMLCollection.prototype is true
 PASS mutationEvent.constructor === window.MutationEvent is true
 PASS mutationEvent.constructor.prototype.__proto__ === window.Event.prototype is true
 PASS successfullyParsed is true
 
 TEST COMPLETE