selftests/bpf: Add tests for non-constant cond_op NE/EQ bound deduction

Add various tests for code pattern '<non-const> NE/EQ <const>' implemented
in the previous verifier patch. Without the verifier patch, these new
tests will fail.

Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230406164500.1045715-1-yhs@fb.com


Signed-off-by: Alexei Starovoitov <ast@kernel.org>