Set apex_available property

The marked library(ies) were available to the APEXes via the
hand-written whitelist in build/soong/apex/apex.go. Trying to remove the
whitelist by adding apex_available property to the Android.bp of the
libraries.

Exempt-From-Owner-Approval: cherry-pick from AOSP

Bug: 150999716
Test: m
Merged-In: Id08058f3105463558c6c82298344a33af0efb2d3
(cherry picked from commit e3d371e3)
Change-Id: Id08058f3105463558c6c82298344a33af0efb2d3