I updated my world to 1.10 and deleted the region files from DIM-1 to get the new nether generation. After looking at known nether fortresses, there are no blaze spawners generated. Blazes do spawn randomly around the nether and the forts generate the same way but there are no spawners anywhere.

Seed is -3862419354477532128 amplified. At cords -100 84 -110 there used to be a double blaze spawner.