intel/compiler: Enable has_iadd3 option on XeHP

intel/compiler: Enable has_iadd3 option on XeHP

shader-db result is inconclusive but doesn't harm to include it for
reference.

Shader-db result on XeHPG:

total instructions in shared programs: 1397405 -> 1397315 (<.01%)
instructions in affected programs: 88252 -> 88162 (-0.10%)
helped: 20
HURT: 7
helped stats (abs) min: 1 max: 18 x̄: 7.20 x̃: 7
helped stats (rel) min: 0.03% max: 2.20% x̄: 0.37% x̃: 0.23%
HURT stats (abs)   min: 4 max: 23 x̄: 7.71 x̃: 4
HURT stats (rel)   min: 0.10% max: 0.68% x̄: 0.22% x̃: 0.11%
95% mean confidence interval for instructions value: -6.81 0.14
95% mean confidence interval for instructions %-change: -0.42% -0.02%
Inconclusive result (value mean confidence interval includes 0).

total cycles in shared programs: 119924219 -> 119931868 (<.01%)
cycles in affected programs: 45029193 -> 45036842 (0.02%)
helped: 11
HURT: 16
helped stats (abs) min: 15 max: 5490 x̄: 1655.73 x̃: 140
helped stats (rel) min: <.01% max: 0.35% x̄: 0.11% x̃: <.01%
HURT stats (abs)   min: 1 max: 2944 x̄: 1616.38 x̃: 1743
HURT stats (rel)   min: <.01% max: 0.17% x̄: 0.09% x̃: 0.10%
95% mean confidence interval for cycles value: -606.11 1172.70
95% mean confidence interval for cycles %-change: -0.04% 0.07%
Inconclusive result (value mean confidence interval includes 0).

v2:
- Include shader-db result (Jason)

Signed-off-by: Sagar Ghuge <sagar.ghuge@intel.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11596>