[3.13] gh-126037: fix UAF in xml.etree.ElementTree.Element.find* when current mutations happen (#127964)
          #131931
        
          
      
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We fix a use-after-free in the
find,findtextandfindallmethods ofxml.etree.ElementTree.Elementobjects that can be triggered when the tag to find implements an__eq__method that mutates the element being queried.(cherry picked from commit c57623c)
xml.etree.ElementTree.Element.find*when concurrent mutations happen #126037