[Bug libstdc++/103924] views::join combined with std::string cannot be used in constant expressions

[ppalka at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103924

--- Comment #7 from Patrick Palka <ppalka at gcc dot gnu.org> ---
N.B. the other testcases in this PR are accepted by GCC 14 after r14-10134.