Avoid accessing live-words bitmap past its size am: 36bf366f46 am: 46d4eeb5ce

Original change: https://android-review.googlesource.com/c/platform/art/+/2240275

Change-Id: Iaf1513cc2e5806b885de2e683ab7378f41e515fa
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>