[PATCH] libstdc++: testsuite: Simplify codecvt_unicode

[Dimitrij Mijoski]

On Wed, 2023-01-18 at 18:53 +0000, Jonathan Wakely wrote:
> This doesn't compile in C++11 or C++14, because there's no guaranteed
> elision.

I see. I just looked up in the docs and found that I need to put
--target_board=unix/-std=c++11 inside RUNTESTFLAGS to test in C++11
mode.