[Perl/perl5] c16355: Add test harness for regexp optimization

[Hugo van der Sanden via perl5-changes]

  Branch: refs/heads/hv/topt
  Home:   https://github.com/Perl/perl5
  Commit: c163559ad1e88675f9c5cba241bd2a1e50771a6b
      
https://github.com/Perl/perl5/commit/c163559ad1e88675f9c5cba241bd2a1e50771a6b
  Author: Hugo van der Sanden <h...@crypt.org>
  Date:   2020-10-06 (Tue, 06 Oct 2020)

  Changed paths:
    A t/re/opt.t

  Log Message:
  -----------
  Add test harness for regexp optimization