Add rust_test and update TEST_MAPPING am: 1807259c44 am: 7a08a1d289 am: 5d70723ca9 am: 0b93b13442

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/futures-task/+/1365231

Change-Id: If883cbc098ea843e15bc0de0e238c7127f609b83