[flexcoders] Crash of safari, firefox using XML.setChildren for XML in a XMLListCollection

[shauncutts]

The following code will crash Flash 9.0 r124 (debug version) when
built with flex builder 3.0: (flash running on either Firefox or
Safari, MacOS)

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml";
layout="vertical"
    creationComplete="dotest();">
    
    <mx:XMLListCollection id="tree_collection">
        <mx:XMLList xmlns="">
            <a>
                <b/>
            </a>
        </mx:XMLList>
    </mx:XMLListCollection>
    <mx:Script>
        <![CDATA[
            public function dotest(): void
            {
                var data:XML = tree_collection[ 0 ];
                data.setChildren( new XMLList() );
            }
                
        ]]>
    </mx:Script>
</mx:Application>