[roll third_party/pigweed] Re-enable asserts in headers

Several parts of the code had commented-out asserts due to DCHECK not
working in headers or constexpr functions. This updates those to use the
pw_assert light API.

Original-Fixes: 246
Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/22820

third_party/pigweed Rolled-Commits: db0992d39c15747..5a0450d263b7de5
Roller-URL: https://ci.chromium.org/b/8850114045662010752
Cq-Cl-Tag: roller-builder:pigweed-experimental-roller
Cq-Cl-Tag: roller-bid:8850114045662010752
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I8d0069b512649d2166058c475d67f4f463720d17
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/40668
Reviewed-by: 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 db0992d..5a0450d 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit db0992d39c15747bea91703d3349e318b5dd801a
+Subproject commit 5a0450d263b7de5e593ed97d4d902b9719977421