Function test_flattening_roundtrip

pub fn test_flattening_roundtrip<T>(input: &T) -> Result<()>
where
    T: Debug + Eq + WitLoad + WitStore,
    <T::Layout as Layout>::Flat: Copy + Debug + Eq,

Test lowering an instance of T, checking that the resulting flat layout matches the expected flat_layout, and check that the instance can be lifted from that flat layout.