texmath-0.13.1.2: test/writer/tex/msup-03.test

<<< native
[ ESuper (ENumber "2") (ENumber "3")
, ESymbol Rel "="
, ESuper
    (ENumber "2")
    (ESuper (ENumber "3") (EPhantom (EIdentifier "fail")))
]
>>> tex
2^{3} = 2^{3^{\phantom{fail}}}