[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/8829722100567999153
Cq-Cl-Tag: roller-builder:pigweed-sample-project-roller
Cq-Cl-Tag: roller-bid:8829722100567999153
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I0a845a31032c09c1b447b7e81663b8bb411daab3
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/sample_project/+/70660
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