[Perl/perl5] 2a7003: gh17746: add missing check on hardcount

[Hugo van der Sanden via perl5-changes]

  Branch: refs/heads/gh17746
  Home:   https://github.com/Perl/perl5
  Commit: 2a70037d3a810eea2c0ae87cc0b2fb3f70e2c8e8
      
https://github.com/Perl/perl5/commit/2a70037d3a810eea2c0ae87cc0b2fb3f70e2c8e8
  Author: Hugo van der Sanden <h...@crypt.org>
  Date:   2022-03-21 (Mon, 21 Mar 2022)

  Changed paths:
    M regexec.c
    M t/re/re_tests

  Log Message:
  -----------
  gh17746: add missing check on hardcount

Failing to check for max iterations caused an assertion failure.