[roll third_party/pigweed] pw_cpu_exception: Snapshot processor integration

Updates pw_cpu_exception to provide integration with the pw_snapshot
processor.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/56382

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 938f08b300747bb..9464931cddc8f06
Roller-URL: https://ci.chromium.org/b/8839150027713846273
Cq-Cl-Tag: roller-builder:pigweed-experimental-roller
Cq-Cl-Tag: roller-bid:8839150027713846273
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I6d29d9468304a027a23a1bb7ca061dc0387666e3
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/56882
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 938f08b..9464931 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 938f08b300747bb8c31e8fd6b339f428924e3cd2
+Subproject commit 9464931cddc8f068e84f1ec8915254d61243174f