message: fixed bug so that fields are returned in order of appearance in bytecode
  Closes:
  Approved by: wrwg
diff: @@ -1079,9 +1079,12 @@ impl<'env> StructEnv<'env> {
  /// Get an iterator for the fields.
  pub fn get_fields(&'env self) -> impl Iterator<Item = FieldEnv<'env>> {
  - self.data.field_data.iter().map(move |(_, data)| FieldEnv {
  + self.data
  + .field_def_idx_to_id
  + .values()
  + .map(move |field_id| FieldEnv {
  struct_env: self.clone(),
  - data,
  + data: &self.data.field_data[field_id],
  })
  }
  