Merge "Add boot animation progress system property." am: a1d897b939 am: 2213bccdb3 am: 2c20709fc9

Original change: https://android-review.googlesource.com/c/platform/frameworks/native/+/1530628

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I93bb6f200629d78e9a1f9d09fad8520139b7c624