Clean up rust_test_host TEST_MAPPING after default update am: ab7dbba14c am: 1e83984d27 am: d4303cb24b am: 3ad4393f74

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: I4a7cc799a571db606b07b8817914079505029bd8