Merge "init: Add a boot monitor for the second stage init" into main am: 2d69dd6055 am: 5e79fd7b35

Original change: https://googleplex-android-review.googlesource.com/c/platform/system/core/+/30846148

Change-Id: I5aa9c4983737fe902664936762fc92fc5395068f
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>