Merge "Add /mnt/vm and mount tmpfs onto it for early VM" into main am: fe4f5a1e am: 3180d59d

Original change: https://android-review.googlesource.com/c/platform/system/core/+/3204633



Change-Id: I598661d32571942699fea3c717691a020276aafa
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>