Change libvixld symbol visibility. am: 4e84745dad am: de2e36a02c am: 09d044cd46

Original change: https://android-review.googlesource.com/c/platform/external/vixl/+/2292134

Change-Id: Id75348553e4ac0aa14325c221e3a32ee63e67bd3
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>