[Perl/perl5] cc365f: t/TEST: trim .DIR extension on VMS

[Craig A. Berry]

  Branch: refs/heads/blead
  Home:   https://github.com/Perl/perl5
  Commit: cc365faa27400f1cbe128133b0ef491a6dd7e913
      
https://github.com/Perl/perl5/commit/cc365faa27400f1cbe128133b0ef491a6dd7e913
  Author: Craig A. Berry <craigbe...@mac.com>
  Date:   2023-04-15 (Sat, 15 Apr 2023)

  Changed paths:
    M t/TEST

  Log Message:
  -----------
  t/TEST: trim .DIR extension on VMS

Otherwise the test suite dies with:

Can't read op/hook.DIR/require.t.

The problem never arose until 93f6f9654a81b66c4 added another
directory one level down from those immediately under t/.