message: test: fix execution_result printer
diff: @@ -16,7 +16,7 @@ std::ostream& operator<<(std::ostream& os, execution_result result)
  std::string_view separator;
  for (const auto& x : result.stack)
  {
  - os << x << separator;
  + os << separator << x;
  separator = ", ";
  }
  os << ")";
  