r600/sfn: register allocation fails for a number of piglits and deqp tests
Scheduling and register allocation is not very robust, currently only one attempt is made and when this fails, the bets are off.
Failing piglit:
- spec@glsl-1.50@execution@variable-indexing@gs-output-array-vec4-index-wr
Failing deqp tests from groups:
- dEQP-GLES31.functional.ssbo.layout.*
- dEQP-GLES31.functional.atomic_counter.*