$ > adb shell
generic_x86:/ $
generic_x86:/ $ exit
$ > adb root
restarting adbd as root
$ > adb shell
generic_x86:/ #

If you get adbd cannot run as root in production builds, you need to modify the config.ini file in ~/.android/avd/DEVICE_ID changing these variables:

PlayStore.enabled = true
image.sysdir.1=system-images\android-27\google_apis_playstore\x86\
tag.display=Google Play
tag.id=google_apis_playstore

Reference