Make which available to product and vendor am: 6e9a8c8b4a am: 63c340b3e5 am: f8c7b779bc am: 62884e502a am: 878f532dd5

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/which/+/2476374

Change-Id: Ia6046f0c9cae0490d06c14363e26e17ce46058a5
Signed-off-by: Automerger Merge Worker <[email protected]>