Generate apex_available from c2a instead of a patch am: 89e0a889bc am: b772c12c88 am: 860c039a4f am: 8ceb2c6d3b

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

Change-Id: Ibcfecae8e531b841cdbe9ba5df99fb933e71875f