ac/nir: abort when an unknown intrinsic is reached

This would have catched this NIR GS lowering regression earlier.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7127>

src/amd/llvm/ac_nir_to_llvm.c

@@ -3783,6 +3783,7 @@ static void visit_intrinsic(struct ac_nir_context *ctx, nir_intrinsic_instr *ins
       fprintf(stderr, "Unknown intrinsic: ");
       nir_print_instr(&instr->instr, stderr);
       fprintf(stderr, "\n");
+      abort();
       break;
    }
    if (result) {