Generate apex_available from c2a instead of a patch am: 89e0a889bc am: b772c12c88 am: 860c039a4f

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/bitflags/+/1688686

Change-Id: I7c211d2e3f34ba07edff5d35d6d9160b97e9a574