texmath-0.12.5: test/writer/tex/msup-01.test

<<< native
[ ESuper (EIdentifier "c") (ENumber "4")
, ESymbol Rel "="
, ESuper
    (EIdentifier "c")
    (EGrouped [ ENumber "4" , EPhantom (EIdentifier "fail") ])
]
>>> tex
c^{4} = c^{4\phantom{fail}}