Clean up rust_test_host TEST_MAPPING after default update am: ab7dbba14c am: 1e83984d27 am: d4303cb24b

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/proc-macro-error-attr/+/1584352

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I84a1a372e9be1f5eebd40a2526dfe26862c40b28