Initialize the appcompat system property folder

Certain applications may have their system properties overlaid with the
contents overlaid for appcompat purposes. Init must initialize the
appcompat folder, same as it does the standard folder.

Bug: 291814949
Ignore-AOSP-First: must be merged with ag/24558703, which has an   Aosp -> internal merge conflict
Test: manual

Change-Id: I0c6a0f66dc543c6e861bc86a417e4feb5ecd7789