wrong evaluation order for splatted args in ref expression

[simeonschaub]

This was pointed out on slack:

julia> Meta.@lower a[f(x), g(y)...]
:($(Expr(:thunk, CodeInfo(
    @ none within `top-level scope`
1 ─ %1 = g(y)
│   %2 = f(x)
│   %3 = Core.tuple(a, %2)
│   %4 = Core._apply_iterate(Base.iterate, Base.getindex, %3, %1)
└──      return %4
))))

I don't see any reason why g(y) should be evaluated before f(x), so this can probably be considered a bug in lowering.