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

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

Change-Id: Iac26d45cb98074566b7a858bad027491dca2b012
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>