Update TEST_MAPPING am: 4ac1d78d69

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/either/+/2107317

Change-Id: Icaafa4f4f06ea1bfe5e47a10d843e37123e7050f
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>