texmath-0.12.5: test/roundtrip/msubsupBsize2.native

[ ESubsup (ESymbol Op "\8747") (ENumber "0") (ENumber "1")
, ESymbol Bin "+"
, ESubsup
    (EFraction NormalFrac (EIdentifier "x") (EIdentifier "y"))
    (ENumber "0")
    (EIdentifier "a")
, ESymbol Bin "+"
, ESubsup
    (EFraction NormalFrac (EIdentifier "x") (EIdentifier "y"))
    (ENumber "0")
    (ENumber "1")
, ESymbol Bin "+"
, ESubsup (ESymbol Op "\8747") (ENumber "0") (EIdentifier "a")
]