Add seal if ashmem-dev is backed by memfd am: 61a2897733 am: 7878e7c9b7

Original change: https://googleplex-android-review.googlesource.com/c/platform/system/core/+/24776869

Change-Id: Ie42fc973da02230d438455935f26458f8f94355f
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>