Merge "Block SHELL_UID from overlay fabricate and clear shell overlays on boot" into sc-dev am: 987cfe1bff am: 872a1ba1e3

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/16077739

Change-Id: I260594ea90870510b36c336b7bf1e0b90a03ce10