Migrate to cargo_embargo. am: 16a2c62f18 am: c5641d58df

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/futures-test/+/2815987

Change-Id: I5947372192cc755d5e8478fcaf1a72a0404f3b14
Signed-off-by: Automerger Merge Worker <[email protected]>