We don't want to add grouping to strings like "-inf", and there is no
radix character to replace either.
libstdc++-v3/ChangeLog:
PR libstdc++/114863
* include/std/format (__formatter_fp::format): Only use
_M_localized for finite values.
* testsuite/std/format/functions/format.cc: Check localized
formatting of NaN and initiny.
(cherry picked from commit 7501c0a397fcf609a1ff5f083746b6330b89ee11)
7a00c459cb