Merge "Clean up rust_test_host TEST_MAPPING after default update" am: 8e7b3701dc

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/cexpr/+/1590594

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: Icceb95c47114175dcfe64130d506d3c3855035b6