Clean up rust_test_host TEST_MAPPING after default update am: b1005cf632 am: f89968cee8

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/libz-sys/+/1584585

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I1eb5616521a8cb08367516620f854004f6a11eea