[automerger skipped] Add support for only starting 64 bit zygote. am: 70052ec8 -s ours

am skip reason: Merged-In Id37a223c73f9a61868b2e26450ef4b6964f7b496 with SHA-1 da94c7f6 is already in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/system/core/+/19272483



Change-Id: I30d387c86c086586958817bab0c60fa441bf80cf
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>