texmath-0.13: test/writer/mml/mi2.test

<<< native
[ EMathOperator "sin" , ESymbol Ord "\8289" , EIdentifier "x" ]
>>> mml
<?xml version='1.0' ?>
<math display="block" xmlns="http://www.w3.org/1998/Math/MathML">
  <mrow>
    <mrow>
      <mi mathvariant="normal">sin</mi>
      <mo>&#8289;</mo>
    </mrow>
    <mi>x</mi>
  </mrow>
</math>