Clean up rust_test_host TEST_MAPPING after default update am: 1397d1fa26 am: 382fd0e8df am: 1e637777f4

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/ring/+/1582783

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I07e8cf0d31669df44ec6f1117b2732ac2aa5fa48