Upgrade emulator to emu-master-dev build 8748233 am: 4ad9d9fb27

Original change: https://googleplex-android-review.googlesource.com/c/platform/prebuilts/android-emulator/+/19014779

Change-Id: I21ebc1335d5762f41742495c896b390b5e0dc541
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>