selftests/bpf: Add more stats into veristat

Extend veristat to collect and print more stats, namely:
  - program size in instructions
  - jited program size in bytes
  - program type
  - attach type
  - stack depth

Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20241209130455.94592-1-mykyta.yatsenko5@gmail.com