DO NOT MERGE - Add flag to turn on/off the headless user specific blacklist/whitelist

Bug: 145626101
Test: manual: set config_systemUserPackagesBlacklistSupported
build and flash
Verify with: 1. adb shell dumpsys package packages
2. adb logcat | grep "blacklist"

Change-Id: I5b45fc86e4c5008933bf361d5bb32a2c17259655
(cherry picked from commit d1c59ec220e95f881feefb55eb099b6f602d4e05)