intel/compiler: remove branch weight heuristic

Current logic is too simple and helps only a small number of cases, harming more common ones.

As a result of this patch, the compiler chooses SIMD32 shaders more frequently.

Jason Ekstrand described the problem here: Does subgroup/wave size matter?

In Intel perf CI it improves FPS in:

	gen9	gen11
gfxbench5 alu2	21.92%	23.7%
synmark OglShMapVsm	3.26%	4.52%
gfxbench5 car chase	1.34%	1.32%

No observed regressions.

In my testing, it also improves FPS in:

	gen9	gen11
The Talos Principle	2.9%	(not tested)

The other 16 games I tested had very minor changes in performance (2/3 positive, but either not significant enough to list here or too noisy).

cc @currojerez