Remove deprecated boot_images property from ART apex am: fac1a9a6f9 am: 9f6aa5d27a am: 6aaad0b1d8

Original change: https://android-review.googlesource.com/c/platform/art/+/1679385

Change-Id: I71bf33dc5d045dd90e0d073cb93ab4b1d0c9e897