Stubs dependency is not installed

When the stubs variant of a library is dependend by a platform component
and the library is included in one or more APEX, the library is not
installed to the platform, because it is provided by APEX.

Bug: 120266448
Test: m
Test: add stubs: { versions: ["1"], }, to libnetd_resolv
then build netd. libnetd_resolv.so does not exist under /system.

Change-Id: I09b78e38df285033ef6e9c85f7ea4b0274e85070