[roll third_party/pigweed] pw_transfer: Remove duplicated test line

This line was accidentally copied & pasted.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/122952

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 49f9451b35b4c02..f15937dffb591ce
Roller-URL: https://ci.chromium.org/b/8790863262676252673
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Ia5e08d818a817ef6889f9cc50bd322a07c1c10df
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/126981
Bot-Commit: Pigweed Integration Roller <pigweed-integration-roller@pigweed.google.com.iam.gserviceaccount.com>
Commit-Queue: Pigweed Integration Roller <pigweed-integration-roller@pigweed.google.com.iam.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index 49f9451..f15937d 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 49f9451b35b4c02f7431b5b99a67087c05573160
+Subproject commit f15937dffb591ce091aa79a0e39f669b1088b454