[frontend][pytorch] Add a new test case for torch aten::fill_ operator implementation

[oviazlo]

Add a new test case for torch aten::fill_ operator implementation.

This new test is testing a case of usage of a sequence of operators aten::div() and aten::fill_() that was causing a failure during the deployment of Mask R-CNN model (torchvision 0.13.0 version of the model).

Issue: #12844

[masahi]

You need to include my change in frontend/pytorch.py from https://github.com/apache/tvm/issues/12844 as well.

[oviazlo]

Thanks for the comment. I have included yours changes as well to the PR.