[roll third_party/pigweed] pw_allocator: Add size reporting

This adds a simple size report for some of the initial components of the
pw_allocator module.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/178370

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: f48b7c0db427b8f..99196c2972ba716
Roller-URL: https://ci.chromium.org/b/8765765708954480817
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I1909dbbea9df5385a308b204ebebf36f5d5d766a
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/178398
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index f48b7c0..99196c2 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit f48b7c0db427b8f7ecd5901cf20e3a9a51744804
+Subproject commit 99196c2972ba71677be6a84a33698902076e1837