texmath-0.12.5: test/roundtrip/msubsup-12.native

[ ESubsup (EIdentifier "V") (EIdentifier "m") (EIdentifier "n")
, ESymbol Rel "="
, EUnderover
    False
    (ESubsup (EIdentifier "V") (EIdentifier "m") (EIdentifier "n"))
    (EPhantom (EText TextNormal "d"))
    (EPhantom (EText TextNormal "d"))
]