Replace emulator_system.mk with multidisplay.mk am: 86e50cfebf am: dd51b548e4 am: 6d86e99d22

Original change: https://android-review.googlesource.com/c/device/generic/car/+/2813935

Change-Id: I3e5808a3160e4e098e39fa10f5f5458642bab81e
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>