WIP: intel: Use a better algorithm in brw_nir_analyze_ubo_ranges

Shader-db results with iris on ICL (without Deux Ex: Mankind Divided):

total instructions in shared programs: 14478207 -> 14445391 (-0.23%)
instructions in affected programs: 1378208 -> 1345392 (-2.38%)
helped: 6019
HURT: 37
helped stats (abs) min: 3 max: 45 x̄: 5.51 x̃: 3
helped stats (rel) min: 0.22% max: 13.64% x̄: 3.07% x̃: 2.64%
HURT stats (abs)   min: 3 max: 28 x̄: 9.65 x̃: 7
HURT stats (rel)   min: 0.12% max: 1.20% x̄: 0.60% x̃: 0.56%
95% mean confidence interval for instructions value: -5.52 -5.31
95% mean confidence interval for instructions %-change: -3.10% -3.01%
Instructions are helped.

total cycles in shared programs: 205710790 -> 205130459 (-0.28%)
cycles in affected programs: 116902116 -> 116321785 (-0.50%)
helped: 16184
HURT: 12006
helped stats (abs) min: 1 max: 8471 x̄: 60.81 x̃: 11
helped stats (rel) min: <.01% max: 52.21% x̄: 5.26% x̃: 1.25%
HURT stats (abs)   min: 1 max: 12746 x̄: 33.64 x̃: 6
HURT stats (rel)   min: <.01% max: 44.95% x̄: 2.26% x̃: 0.81%
95% mean confidence interval for cycles value: -22.88 -18.29
95% mean confidence interval for cycles %-change: -2.15% -1.97%
Cycles are helped.

total spills in shared programs: 5641 -> 5698 (1.01%)
spills in affected programs: 1341 -> 1398 (4.25%)
helped: 0
HURT: 27

total fills in shared programs: 5296 -> 5356 (1.13%)
fills in affected programs: 2262 -> 2322 (2.65%)
helped: 0
HURT: 27

total sends in shared programs: 711474 -> 700416 (-1.55%)
sends in affected programs: 65458 -> 54400 (-16.89%)
helped: 6046
HURT: 10
helped stats (abs) min: 1 max: 15 x̄: 1.83 x̃: 1
helped stats (rel) min: 0.70% max: 75.00% x̄: 21.97% x̃: 20.00%
HURT stats (abs)   min: 1 max: 1 x̄: 1.00 x̃: 1
HURT stats (rel)   min: 5.88% max: 5.88% x̄: 5.88% x̃: 5.88%
95% mean confidence interval for sends value: -1.86 -1.79
95% mean confidence interval for sends %-change: -22.22% -21.62%
Sends are helped.

LOST:   19
GAINED: 3

All of the programs with additional spilling in this group are dolphin ubershaders.

Shader-db results for Deux Ex: Mankind Divided with iris on ICL:

total instructions in shared programs: 1567968 -> 1579413 (0.73%)
instructions in affected programs: 920802 -> 932247 (1.24%)
helped: 586
HURT: 307
helped stats (abs) min: 3 max: 36 x̄: 9.09 x̃: 7
helped stats (rel) min: 0.15% max: 9.15% x̄: 2.87% x̃: 2.54%
HURT stats (abs)   min: 2 max: 160 x̄: 54.63 x̃: 34
HURT stats (rel)   min: 0.07% max: 8.35% x̄: 2.61% x̃: 1.65%
95% mean confidence interval for instructions value: 10.09 15.54
95% mean confidence interval for instructions %-change: -1.20% -0.77%
Inconclusive result (value mean confidence interval and %-change mean confidence interval disagree).

total cycles in shared programs: 131965209 -> 130752603 (-0.92%)
cycles in affected programs: 113877187 -> 112664581 (-1.06%)
helped: 801
HURT: 256
helped stats (abs) min: 1 max: 13821 x̄: 2202.44 x̃: 208
helped stats (rel) min: <.01% max: 35.05% x̄: 6.25% x̃: 3.11%
HURT stats (abs)   min: 1 max: 107410 x̄: 2154.50 x̃: 35
HURT stats (rel)   min: <.01% max: 54.38% x̄: 2.61% x̃: 0.96%
95% mean confidence interval for cycles value: -1460.19 -834.24
95% mean confidence interval for cycles %-change: -4.57% -3.65%
Cycles are helped.

total spills in shared programs: 3783 -> 6507 (72.01%)
spills in affected programs: 2048 -> 4772 (133.01%)
helped: 0
HURT: 307

total fills in shared programs: 5248 -> 8135 (55.01%)
fills in affected programs: 2950 -> 5837 (97.86%)
helped: 0
HURT: 307

total sends in shared programs: 102946 -> 100242 (-2.63%)
sends in affected programs: 67112 -> 64408 (-4.03%)
helped: 893
HURT: 0
helped stats (abs) min: 1 max: 12 x̄: 3.03 x̃: 3
helped stats (rel) min: 0.62% max: 42.86% x̄: 11.64% x̃: 8.33%
95% mean confidence interval for sends value: -3.15 -2.90
95% mean confidence interval for sends %-change: -12.34% -10.95%
Sends are helped.

LOST:   4
GAINED: 0