Update TEST_MAPPING am: 6d9f687c41

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/shlex/+/2411802

Change-Id: I66a5b989738a34adbd510cb0d6f5bf43955cc5cf
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>