Clean up rust_test_host TEST_MAPPING after default update am: 7ef4c8aa23 am: 8c8d5627ec am: 9d2fe1e09c am: c33c8c426e

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/ppv-lite86/+/1584563

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I45e820e69f6dea1d4adc2f8ce4543ea0537a1f3c