roll: third_party/pigweed pw_allocator: Add UniquePtr::MakeUniqueArray

This CL adds MakeUniqueArray to UniquePtr, which allows
UniquePtr to hold an array of elements.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/239913
Original-Revision: 9aae89c7bab1de5a914c462f814fec6528e27a0f

Rolled-Repo: https://pigweed.googlesource.com/pigweed/pigweed
Rolled-Commits: 60e7e4fa95cbab..9aae89c7bab1de
Roller-URL: https://ci.chromium.org/b/8734504985734789793
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I3122f9a565ebedb25ed3ae9ece7b8247255143a5
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/241293
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index 60e7e4f..9aae89c 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 60e7e4fa95cbabcd0b6cb8948d90d8ba15e92919
+Subproject commit 9aae89c7bab1de5a914c462f814fec6528e27a0f