Generate apex_available from c2a instead of a patch am: 80be90f058 am: e325c01929 am: ee1464a0c5

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/futures-core/+/1688766

Change-Id: I1a09ec0642c28411022fa6686ea523f3fd7a316f