[roll third_party/pigweed] pw_allocator: Clean up LibCAllocatorTest

This CL simply removes an unneeded test fixture.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/206173

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: c50cd3d84714aa6..32ff69e60cb8ad6
Roller-URL: https://ci.chromium.org/b/8749728671424438721
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Ia819bea115977ebad619a8fd1380778f90f01cf1
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/examples/+/206370
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.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 c50cd3d..32ff69e 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit c50cd3d84714aa6f29c1a7708db68dfd888a2715
+Subproject commit 32ff69e60cb8ad67d68471f7b3017bc9c7dbfae9