Use APK CtsShim prebuilts for flattened apex.

Fix: 158036322
Test: built flame-userdebug with m OVERRIDE_TARGET_FLATTEN_APEX=true, ran
atest CtsAppSecurityHostTestCases:android.appsecurity.cts.PrivilegedUpdateTests#testDisableUpdatedSystemApp
and verified that the cts shim apex is not installed

Change-Id: I9d558f2ad3409b5104a9b9fc0aebb28689a822d9
Merged-In: I9d558f2ad3409b5104a9b9fc0aebb28689a822d9
(cherry picked from commit c15cbac0d961c865aaecfbd9735b37613a3751b4)
1 file changed