I created a Breton Arcanist specifically to see how well that helped with sustain but it doesn't appear as if the Breton racial bonuses are being calculated - I say this based on looking at magicka costs for some old standby skills in the regular game and comparing them to what I'm seeing here on PTS (specifically in the live game the Psijic spammable can be brought down to 18xx magicka per use and it doesn't get any lower than 20xx magicka on PTS).