Add more comments about the return codes of profman. am: 99fc5bb7a7 am: 4eb3f0a6ff am: 69ab0e7141 am: b4017524cd

Original change: https://android-review.googlesource.com/c/platform/art/+/2203780

Change-Id: I12120dcaa15575ff5d2e1497a099b2a4856c8ef0
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>