radv: CSE ray_launch_{size|id}

radv: CSE ray_launch_{size|id}

Stats for Q2RTX
Totals from 7 (0.01% of 134913) affected shaders: (GFX10.3)

VGPRs: 736 -> 704 (-4.35%)
CodeSize: 204424 -> 204400 (-0.01%); split: -0.03%, +0.02%
MaxWaves: 67 -> 69 (+2.99%)
Instrs: 37540 -> 37549 (+0.02%); split: -0.02%, +0.04%
Latency: 973556 -> 973267 (-0.03%)
InvThroughput: 209068 -> 200902 (-3.91%)
VClause: 920 -> 921 (+0.11%); split: -0.11%, +0.22%
SClause: 1045 -> 1043 (-0.19%)
Copies: 4853 -> 4865 (+0.25%); split: -0.08%, +0.33%
Branches: 1571 -> 1578 (+0.45%)
PreSGPRs: 421 -> 407 (-3.33%)
PreVGPRs: 638 -> 632 (-0.94%)
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21156>