texmath-0.12.5: test/writer/tex/msup-07.test

<<< native
[ ESuper (EIdentifier "a") (ENumber "2")
, ESymbol Rel "="
, ESuper
    (EIdentifier "a")
    (EOver False (ENumber "2") (EPhantom (EIdentifier "x")))
]
>>> tex
a^{2} = a^{\overset{\phantom{x}}{2}}