Generate apex_available from c2a instead of a patch am: 4fa481b6ab am: c09fc84c6f am: e4add52767 am: 054fe6274a

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/futures-util/+/1688788

Change-Id: I3d476461fa305cc089e342fa807280eecff8081f