[Perl/perl5] cf0a1d: safer cleanup when failing to compile regexps

[Tony Cook via perl5-changes]

  Branch: refs/heads/smoke-me/tonyc/21661-no-warn-ck
  Home:   https://github.com/Perl/perl5
  Commit: cf0a1dd00724c70526c707cd2fdd66d4e378829f
      
https://github.com/Perl/perl5/commit/cf0a1dd00724c70526c707cd2fdd66d4e378829f
  Author: Tony Cook <t...@develop-help.com>
  Date:   2023-11-29 (Wed, 29 Nov 2023)

  Changed paths:
    M regcomp.c
    M regcomp_internal.h

  Log Message:
  -----------
  safer cleanup when failing to compile regexps

(needs more commit message, I want CI/smokes)

Fixes #21661