Regression fix for document.all(undefined)

This makes document.all(undefined) behave like
document.all.item(undefined). The intent of
0679448 was to be editorial, but it
accidentally made these cases different.

There was already a test for this, submitted at the same time as the
supposed-editorial change:
https://github.com/w3c/web-platform-tests/blob/b6d42d0174fd24bda0802f8a55ee46381092ef80/html/infrastructure/common-dom-interfaces/collections/htmlallcollection.html#L209

Author: foolip

source

@@ -7478,8 +7478,8 @@ interface <dfn>HTMLAllCollection</dfn> {
   <h6 id="HTMLAllCollection-call">[[Call]] ( <var>thisArgument</var>,  <var>argumentsList</var> )</h6>
 
   <ol>
-   <li><p>If <var>argumentsList</var>'s <span data-x="list size">size</span> is zero, return
-   null.</p></li>
+   <li><p>If <var>argumentsList</var>'s <span data-x="list size">size</span> is zero, or if
+   <var>argumentsList</var>[0] is undefined, return null.</p></li>
 
    <li><p>Let <var>nameOrIndex</var> be the result of <span
    data-x="concept-idl-convert">converting</span> <var>argumentsList</var>[0] to a <code