Introduce Soong target libmemoffset_nostd am: 46edeb14c3

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/memoffset/+/2952669

Change-Id: Iec9c31d4618c16881660289e93b9640a62b0bc06
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>