Merge "rust_library targets to build stdlibs from source" into main am: b8e776611e am: 773181b4b8

Original change: https://android-review.googlesource.com/c/platform/prebuilts/rust/+/2721453

Change-Id: I0c2c8e5eb97877bfb2b073c0c0e93668da8451e2
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>