[perl #128630] follow-up on 6151d433

[perl #128630] follow-up on 6151d433

- test explicitly for $^O equivalence (faster, simpler),
  as suggested in #126380
- allow also \b-/i match of archname
- however, do not explicitly anchor the archname,
  as suggested in #126380, since if the regexp needs that, it can do so
- \Q-\E-protect the $^O, for paranoia
- for skip, use test.pl skip() instead of ok(1),
  pointed out privately by Dan Collins
- drop the newly added /xxx/ functionality to simplify things