[roll third_party/pigweed] pw_unit_test: Support ResultDB upload

Produces more structured MILO UI results on test failures. This is just
an MVP; we should improve it down the road.

Original-Bug: 247857184
Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/111472

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: eda41b1e6b7edef..0f6818d346a63bb
Roller-URL: https://ci.chromium.org/b/8801940632661476785
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I6404a3adcf93cf0a8c7bfd5337e0e8726208f240
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/111990
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 eda41b1..0f6818d 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit eda41b1e6b7edefdcf76d0ce4eecfc3695885ee5
+Subproject commit 0f6818d346a63bb214d77086bf66f4bb020edf40