[TorchToLinalg] Support lowering AtenMaxUnpool2dOp for linalg backend (#4265)

The change adds support to lower AtenMaxUnpool2dOp for linalg backend.
Existing lowering for AtenMaxUnpool3dOp is refactored such that 2d/3d
variants share utils

Unlike max_unpool3d, max_unpool2d does not support specification of
stride, padding
[torch op
registry](https://github.com/pytorch/pytorch/blob/7451dd058564b5398af79bfc1e2669d75f9ecfa2/torch/csrc/jit/passes/utils/op_registry.cpp#L21)

The default values of stride and padding
https://docs.pytorch.org/docs/stable/generated/torch.nn.MaxUnpool2d.html

Closes #4255

Author: vinitdeodhar