Make cexpr available to product and vendor am: 94fcfdd31c am: 62354a6a29 am: 0baa64985b am: 624b836711

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/cexpr/+/2476330

Change-Id: Ia86dbf90a13552707a002522399bdd19ff3c9da1
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>