Add a few unit tests for BTF_KIND_ENUM64 deduplication. Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20220607062713.3725409-1-yhs@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>