Add visibility: to limit access to lua. am: 128b199183 am: c9afa34d74 am: a698482252 am: 4e5eae54b8 am: f12353fbe8

Original change: https://android-review.googlesource.com/c/platform/external/lua/+/1424972

Change-Id: I0bfbff53bc942cfa4ff8c657ae50c98cdee43f06