Cleanup: remove ro.apex.updatable usage

"flattened" apexes are no longer supported and ro.apex.updatable should
be always true.

Bug: 297460439
Test: atest CtsApexTestCases
Test: atest CtsInstallTestCases
Test: atest CtsRollbackManagerHostTestCases
Test: atest CtsStagedInstallHostTestCases
Test: atest CtsContentTestCases:PackageManagerTest
Merged-In: I758ee62d1d8e5862d19dc1f922ce264fd8e82695
Change-Id: I758ee62d1d8e5862d19dc1f922ce264fd8e82695
(cherry picked from commit 40f55e51eda947c381aa2df9ea455810ce2ea2f0)
12 files changed