ANDROID: rust: sync: add `ArcBorrow::from_raw`

A dependency of the Rust linked list.

This patch is an unmodified version of a patch included in the list of
dependencies of the Rust Binder RFC [1]. It is marked ANDROID: because
it has not yet been sent to the mailing list. It needs to be rebased on
top of [2] before it can be sent.

Link: https://lore.kernel.org/rust-for-linux/20231101-rust-binder-v1-0-08ba9197f637@google.com/ [1]
Link: https://lore.kernel.org/all/20240205091842.2858516-1-aliceryhl@google.com/

 [2]
Bug: 324206405
Change-Id: I80322e059774e6381556dce1aad909e6a4ea31fe
Signed-off-by: Alice Ryhl <aliceryhl@google.com>