Re: [PATCH v2 0/6] MR9403: vccorlib140: Implement stringification functions.

[Vibhav Pant (＠vibhavp)]

v2:
* Simplify `tostring_impl`.
* Reuse `_ToString()` functions in `__abi_ObjectToString`.
* Rewrite `HSTRING_SPRINTF` as a function.