texmath-0.12.5: test/writer/mml/mstyleA2.test

<<< native
[ EStyled
    TextBoldItalic
    [ EGrouped [ ENumber "2" , ESymbol Bin "+" , EIdentifier "x" ] ]
]
>>> mml
<?xml version='1.0' ?>
<math display="block" xmlns="http://www.w3.org/1998/Math/MathML">
  <mstyle mathvariant="bold-italic">
    <mrow>
      <mn>2</mn>
      <mo>+</mo>
      <mi>𝒙</mi>
    </mrow>
  </mstyle>
</math>