[roll third_party/pigweed] pw_presubmit: No env_with_clang_vars with bazel

Bazel has its own mechanisms for toolchain selection, see
https://bazel.build/extending/toolchains#toolchain-resolution

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/173656

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: f480cb2249645c5..97a92fc373e9035
Roller-URL: https://ci.chromium.org/b/8768246403863016161
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I5b399f2f748d1ed123a924aa00bcb371688b74bb
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/173873
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 f480cb2..97a92fc 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit f480cb2249645c5131466aa65286659775846a52
+Subproject commit 97a92fc373e9035cb057b65307b26d27124e243a