selftests/bpf: Verify struct_ops autoload/autocreate sync

Check that autocreate flags of struct_ops map cause autoload of
struct_ops corresponding programs:
- when struct_ops program is referenced only from a map for which
  autocreate is set to false, that program should not be loaded;
- when struct_ops program with autoload == false is set to be used
  from a map with autocreate == true using shadow var,
  that program should be loaded;
- when struct_ops program is not referenced from any map object load
  should fail.

Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240306104529.6453-10-eddyz87@gmail.com