message: Rewrite Freeze for VecMap without into_try_map
  Summary: Following diff removes `into_try_map`.
diff: @@ -188,7 +188,13 @@ where
  type Frozen = VecMap<K::Frozen, V::Frozen>;
  fn freeze(self, freezer: &Freezer) -> anyhow::Result<Self::Frozen> {
  - self.into_try_map(|k, v| Ok((k.freeze(freezer)?, v.freeze(freezer)?)))
  + let mut result = VecMap::with_capacity(self.len());
  + for (key, value) in self.into_iter_hashed() {
  + let key = key.freeze(freezer)?;
  + let value = value.freeze(freezer)?;
  + result.insert_unique_unchecked(key, value);
  + }
  + Ok(result)
  }
  }
  