Generate apex_available from c2a instead of a patch am: bf8e4adbf9 am: e87e21a722 am: a908324b73

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/shared_child/+/1689917

Change-Id: I14ddd959c5c1f0eddf54209c4ed314137e71364c