Mark updatable APEXes

Mark updatable APEXes as updatable: true so that they are opted-out from
optimizations that make sense only for non-updatable modules; such as
symlinking to the libs in the system partition.

Bug: 149805758
Test: m and check that there is no symlink from the APEX to the system
partition.

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

Merged-In: Id21fa176acce4800fb8e6c723007f6a4aa2d1bab
(cherry picked from commit f3d123910b4c899b3aed8d82272fa5d24b6dc426)
Change-Id: Id21fa176acce4800fb8e6c723007f6a4aa2d1bab