Use userfaultfd in COPY mode even when minor-fault available am: 41af30d7d4

Original change: https://android-review.googlesource.com/c/platform/art/+/2393852

Change-Id: Ibef42e355b858b9804fe070e2f919bc82c6154be
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>