texmath-0.12.5: test/writer/mml/msup-05.test

<<< native
[ ESuper (EIdentifier "x") (ENumber "3")
, ESymbol Rel "="
, ESuper (EIdentifier "x") (ENumber "3")
]
>>> mml
<?xml version='1.0' ?>
<math display="block" xmlns="http://www.w3.org/1998/Math/MathML">
  <mrow>
    <msup>
      <mi>x</mi>
      <mn>3</mn>
    </msup>
    <mo>=</mo>
    <msup>
      <mi>x</mi>
      <mn>3</mn>
    </msup>
  </mrow>
</math>