Does this apply to the internal build system as well? As far as I know this issue still has not been addressed in recent Android system images for Pixel devices: https://twitter.com/landaire/status/1152739987869167616
Those haven't been released in Android yet, but they should be in the next quarterly release of Android. My understanding from chatting with the Android team is that though this is a weakened mitigation, it is not an exploit.