bpo-28009: Fix uuid SkipUnless logic to be based on platform programs capable of...

bpo-28009: Fix uuid SkipUnless logic to be based on platform programs capable of introspection (GH-12777)

uuid could try fallback methods that had no chance of working on a particular
platform, and this could cause spurious test failures, as well as degraded
performance as fallback options were tried and failed.

This fixes both the uuid module and its test's SkipUnless logic to use a
prefiltered list of techniques that may at least potentially work on that platform.

Patch by Michael Felt (aixtools).
(cherry picked from commit 3a1d50e7e573efb577714146bed5c03b9c95f466)

Co-authored-by: Michael Felt <aixtools@users.noreply.github.com>