armv7-a-neon: ASSUMPTIONS R GOOD, KAY?!

Summary:
...these actually are good and assumptions for us to be making.
Also fixes our b0rked krait handling.

Test Plan: Still in an early testing phase, bare with me a bit.

Reviewers: randall.rushing, Mustaavalkosta, Roach

Differential Revision: http://review.codefirex.com/D219

Change-Id: Idcf8b0743a4b0d083cb64fbff253d8956e5c949d