Merge changes from topic "board-system-ext-sepolicy" am: 6d34f734 am:...

Merge changes from topic "board-system-ext-sepolicy" am: 6d34f734 am: 62b08d28 am: 597d3816 am: 0d142625

Original change: https://android-review.googlesource.com/c/platform/build/+/1273731

Change-Id: Ib8642e7811fb74a228f6d9079f1a8e8ecc6b9277