Prepare for libnative{bridge,loader} moving to art/

Add temporary public visibility for libraries.

Update bpfmt for ART's repohooks.

Bug: 137364733
Test: m nothing
Test: copy libs to art/, create a CL, run repohooks, m nothing.

Change-Id: Ib9a280136e4b992fe17b8943cf404c9c803efb8d