Remove instructions from dead blocks when building the dominator tree am: 7023bf8227 am: 8880c14298 am: 4adb3eb29b

Original change: https://android-review.googlesource.com/c/platform/art/+/2190021

Change-Id: I3b9cb228b461696d69747ec8543d14d1f4f04017
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>