bpf_testmod_union_arg_2
int BPF_PROG2(test_union_arg_2, int, a, union bpf_testmod_union_arg_2, b)
bpf_testmod_test_union_arg_2(int a, union bpf_testmod_union_arg_2 b)
union bpf_testmod_union_arg_2 union_arg2 = { .arg = {2, 3} };