[Perl/perl5] b39dd1: sv_isa_sv() no longer considered experimental

[Paul Evans via perl5-changes]

  Branch: refs/heads/blead
  Home:   https://github.com/Perl/perl5
  Commit: b39dd1437776f3287197693df0c88a7a0bba3913
      
https://github.com/Perl/perl5/commit/b39dd1437776f3287197693df0c88a7a0bba3913
  Author: Paul "LeoNerd" Evans <leon...@leonerd.org.uk>
  Date:   2023-11-23 (Thu, 23 Nov 2023)

  Changed paths:
    M embed.fnc

  Log Message:
  -----------
  sv_isa_sv() no longer considered experimental