[relay][simplify_expr]: Add pass to remove trivial transpose ops

[f2013519]

With my BYOC flow, I see that during various transformations, sometimes trivial no-ops like relay.transpose(x, axes=[0, 1, 2, 3]) are created. I would expect these to be optimized out with the SimplifyExpr pass which is not happening currently. This creates issues when I try to perform pattern matching on the graph.

Currently, SimplifyExpr looks for back to back transpose ops to optimize. This PR splits the current pass into two allowing us to optimize out these trivial ops as well.

[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 @shingjan _{See #10317 for details}

_{Generated by tvm-bot}

[f2013519]

cc @shingjan @junrushao @masahi