The style `border-spacing` of parent element affects fractions rendering

Created by: kwankyu

This is observed with MathJax3 with CHTML rendering. For example,

      <table style="border-spacing:20px">
          <tr><td><span>$\frac{1}{2}$</span></td></tr>
      </table>   

display the fraction with too much spacing. SVG rendering is okay.