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: Ic3edc7e285e9eafbdaa20b18ccbc0b2231370779
(cherry picked from commit 7c2ae1f0)
Change-Id: Ic3edc7e285e9eafbdaa20b18ccbc0b2231370779