radv,aco: don't end monolithic ray tracing with unconditional terminate

The terminate requires more code and blocks us from deallocating VGPRs early.

Foz-DB Navi31:
Totals from 63 (0.08% of 80273) affected shaders:
Instrs: 3372702 -> 3372467 (-0.01%)
CodeSize: 17441676 -> 17440736 (-0.01%)
Latency: 19763447 -> 19763288 (-0.00%)
InvThroughput: 3860502 -> 3860478 (-0.00%)
Branches: 96204 -> 96141 (-0.07%)
SALU: 406648 -> 406549 (-0.02%)

Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/37542>

src/amd/compiler/instruction_selection/aco_select_nir.cpp

@@ -1208,6 +1208,8 @@ select_program_rt(isel_context& ctx, unsigned shader_count, struct nir_shader* c
        */
       if (shader_count > 1 || shaders[i]->info.stage != MESA_SHADER_RAYGEN)
          insert_rt_jump_next(ctx, args);
+      else
+         Builder(ctx.program, ctx.block).sopp(aco_opcode::s_endpgm);
 
       cleanup_context(&ctx);
    }

src/amd/vulkan/nir/radv_nir_rt_shader.c

@@ -2075,9 +2075,7 @@ radv_nir_lower_rt_abi(nir_shader *shader, const VkRayTracingPipelineCreateInfoKH
 
    b.cursor = nir_after_impl(impl);
 
-   if (monolithic) {
-      nir_terminate(&b);
-   } else {
+   if (!monolithic) {
       /* select next shader */
       shader_addr = nir_load_var(&b, vars.shader_addr);
       nir_def *next = select_next_shader(&b, shader_addr, info->wave_size);