Merge "Add system property for the new boot-after-mainline-update compilation...

Merge "Add system property for the new boot-after-mainline-update compilation reason." am: 3f6ffaa3 am: 01a75657

Original change: https://android-review.googlesource.com/c/platform/build/+/2435496



Change-Id: I18d6b2f43dff7280aa79a96f95de909795f25629
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>