Function mz_lowertest::deserialize_generic

pub fn deserialize_generic<D, I>(
    stream_iter: &mut I, 
    type_name: &'static str
) -> Result<D, String> where
    D: DeserializeOwned + MzReflect,
    I: Iterator<Item = TokenTree>, 

Simpler interface for deserialize when no syntax overrides or extensions are needed.