roll: third_party/pigweed b1facaf..bec7844 (4 commits)

bec7844:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/236741 bazel: Remove redundant flags from bazelrc
c5cf4e3:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/215232 pw_thread_freertos: Build unit tests
8a67d6b:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/236454 pw_thread: Mark legacy function* / void* constructor as deprecated
f8994ac:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/236012 pw_bluetooth: Fixes to IsoDataFramePacket

Rolled-Repo: https://pigweed.googlesource.com/pigweed/pigweed
Rolled-Commits: b1facaf899336b..bec7844c86dba5
Roller-URL: https://ci.chromium.org/b/8736436209270732865
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I469a11bfc3508b8986fc71a66ec12a79bd6c5dcc
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/236853
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index b1facaf..bec7844 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit b1facaf899336bcf653e3113ef7cee188e77e0f0
+Subproject commit bec7844c86dba5478a3e4448c96879394be16378