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

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

Change-Id: I7199acf4a6c6cf40fa19196b53ff220a6f0d7917