[roll third_party/pigweed] pw_{sync,thread}: Split up facade unit test cases

Splits up large unit test cases into individual tests.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/70533

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: d5a4220ec991388..4b5ad7d97e5eefc
Roller-URL: https://ci.chromium.org/b/8829722100431455121
Cq-Cl-Tag: roller-builder:pigweed-experimental-roller
Cq-Cl-Tag: roller-bid:8829722100431455121
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Icccdd0ddc80d9f98837b90103ade212a093055fa
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/70535
Bot-Commit: Pigweed Integration Roller <pigweed-integration-roller@pigweed.google.com.iam.gserviceaccount.com>
Commit-Queue: Pigweed Integration Roller <pigweed-integration-roller@pigweed.google.com.iam.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index d5a4220..4b5ad7d 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit d5a4220ec99138895d2f44e4eed2b5eee5537f42
+Subproject commit 4b5ad7d97e5eefc928081268c3e0a059b4aa369b