Define product public libraries

When /product is unbundled from the /system, /product/etc/ may not
have 'public.libraries-<companyname>.txt' to extend public libraries.
Instead, /product/etc/public.library.txt can provide public libraries
from /product.

Bug: 186055799
Test: atest libnativeloader_test
Change-Id: I8994649826657f59ac1dac655205b9704a2c67c9
5 files changed