[Perl/perl5] ce0392: Stop implying "." belongs in $ENV{PATH}

[Tom Hukins]

  Branch: refs/heads/blead
  Home:   https://github.com/Perl/perl5
  Commit: ce039238c523d4cfeaba421697746329fa713515
      
https://github.com/Perl/perl5/commit/ce039238c523d4cfeaba421697746329fa713515
  Author: Tom Hukins <t...@eborcom.com>
  Date:   2020-08-26 (Wed, 26 Aug 2020)

  Changed paths:
    M dist/Env/lib/Env.pm
    M t/porting/known_pod_issues.dat

  Log Message:
  -----------
  Stop implying "." belongs in $ENV{PATH}

Instead, use an arbitrary path that has less chance of encouraging
people to allow the current directory in their path.

This was prompted by #16951 and attached as a patch to that issue which
was mistakenly closed without fixing the problem.