Merge "Block SHELL_UID from overlay fabricate and clear shell overlays on boot" into sc-dev am: 987cfe1b am: 073a98e3 am: dd8e19b1 am: 28b13946

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

Change-Id: I22473409733016bb5a739ed2fac64e4590a377cc