Method reset

crates/c-api/include/wasm.hh:541–546

  template<class T> inline static auto make(own<T>&& x) -> Val;

  void reset() {
    if (is_ref() && impl_.ref) {
      destroyer()(impl_.ref);
      impl_.ref = nullptr;
    }
  }

  void reset(Val& that) {
    reset();