retry³ absl

This merges the two CLs we've been considering,

    1) the first attempt,
       https://skia-review.googlesource.com/c/skia/+/286070;
    2) the roll to latest Abseil LTS branch,
       https://skia-review.googlesource.com/c/skia/+/323076.

(See also the second attempt,
https://skia-review.googlesource.com/c/skia/+/322976.)

We'll need this working in Google3 or punt like we have for Android.

Bug: skia:10165
Cq-Include-Trybots: luci.skia.skia.primary:Canary-G3
Change-Id: Ifb42c1bb2c5e70848208d17b841cdb67bd36e182
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/323158
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
5 files changed