ci: Switch swrast piglit to piglit-runner to speed things up, clean up piglit trace running code and job logs

Motivated by the CI pipelines getting backed up last week, I tried to cut down some of Mesa's x86 runner overhead. From the big commit:

ci/llvmpipe,softpipe: Switch piglit testing to piglit-runner.

The new runner reduces the runtime by about 1/3 thanks to using rust
instead of python, and includes automatic flake handling so you don't just
have to skip flaky tests.  The wrapper script also includes IRC flake
reporting (so one can track and update the flakes list to improve CI
reliability), always uploading results to CI for review (so you can
diagnose flakes and look at timings), has a prettier regressions report
and a helpful timing report, and is the same as what's used by all the HW
runners as well.

The downside is that by dropping the massive list of skips, you no longer
get flagged if Mesa refactors end up accidentally disabling extensions and
thus making tests skip.  For that, I've started on
https://gitlab.freedesktop.org/anholt/deqp-runner/-/merge_requests/33 so
that hardware drivers get extension checking coverage too.

Thanks to the perf improvement, we get to drop one of the jobs for
llvmpipe.

xfail lists were mostly sed-jobs from the prior expectations lists.  The
exceptions to that you'll find in the form of whitespace around the
affected test group (usually changes of capitalization or
special-characters), or an explanation for the more interesting changes
(which thankfully we can now record in the xfails lists!).