[Arith] Fix solve inequality of unbound var ranges

[wrongtest-intellif]

Fix an issue in FindBestRange where if IntSet::max() if inf, it could not take part in general arithmetic computations.

[tvm-bot]

Thanks for contributing to TVM! Please refer to the contributing guidelines https://tvm.apache.org/docs/contribute/ for useful information and tips. Please request code reviews from Reviewers by @-ing them in a comment.

• cc @junrushao _{See #10317 for details}

_{Generated by tvm-bot}