[Perl/perl5] 576cb4: reset(): call set magic when clearing SVs

[Tony Cook via perl5-changes]

  Branch: refs/heads/blead
  Home:   https://github.com/Perl/perl5
  Commit: 576cb40592d9fa7dd79b176acecb10438cb1b626
      
https://github.com/Perl/perl5/commit/576cb40592d9fa7dd79b176acecb10438cb1b626
  Author: Tony Cook <t...@develop-help.com>
  Date:   2023-07-04 (Tue, 04 Jul 2023)

  Changed paths:
    M sv.c
    M t/op/reset.t

  Log Message:
  -----------
  reset(): call set magic when clearing SVs

reset() with an argument would clear the specified SVs when requested
but didn't call set magic, this would result in the effect on magic
variables not applying, such as the $| and $^W used in the ticket.

This isn't a problem for AVs and HVs as their corresponding clear
functions do call the appropriate clear magic.

Fixes #20763