Clean up rust_test_host TEST_MAPPING after default update am: a6e08a0d70 am: 071c19db01 am: 5292e464c4 am: 69bbdf989c

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/url/+/1582765

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I18fb1cc544db2f778f8131afab4b12a84842e213