PASS if no crash or assert.
<fieldset id=fieldSet></fieldset>
<script>
if (window.testRunner)
  testRunner.dumpAsText();
onload = () => {
  document.body.offsetTop;
  fieldSet.style.all = 'unset';
  document.body.offsetTop;
  fieldSet.style.all = 'unset';
  fieldSet.append(document.createElement('span'));
};
</script>