Upgrade emulator to emu-master-dev build 6629878 am: 3dff88bfdd am: 84d1b420f2 am: ce73af9654

Original change: https://android-review.googlesource.com/c/platform/prebuilts/android-emulator/+/1350776

Change-Id: I3e1bb16b89fd3bcda024d995bc88d31571a219eb