roll: third_party/pigweed pw_fuzzer: Improve .bazelrc fuzzing support

This CL drops the fuzztest.bazelrc generated by FuzzTest, and instead
adds imports two new files from //pw_fuzzer: libfuzzer.bazelrc and
fuzztest.bazelrc. These facilitate adding fuzzing support to downstream
projects' .bazelrc files as well.

Additionally, this CL fixes up the Bazel support for FuzzTest. It uses
the //pw_toolchain/host_clang:asan_feature and adds a
//pw_toolchain/host_clang:fuzztest_feature instead of using FuzzTest's
approach of setting {c|link}opts directly.

Finally, this CL extands the same support for libFuzzer, in the form of
//pw_fuzzer/libfuzzer.bazelrc.

Original-Bug: b/347696410
Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/216112
Original-Revision: 993b55e5321ceabcc80c82f25fd5d83f7b5045c4

Rolled-Repo: https://pigweed.googlesource.com/pigweed/pigweed
Rolled-Commits: 82759ccb711c3f..993b55e5321cea
Roller-URL: https://ci.chromium.org/b/8736857958083920689
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: If9d5af7b1037e62eca08e46e5c3691ad9d6108f1
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/235696
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Bot-Commit: 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 82759cc..993b55e 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 82759ccb711c3f34320ae9ae37bf70a029baec57
+Subproject commit 993b55e5321ceabcc80c82f25fd5d83f7b5045c4