Introduce new optimizer Pad + Conv/MaxPool (#18136)
### Description
Introducing new L1 optimizer to fuse Pad to it's child node if the child
node is Conv or MaxPool.
Pad -> Conv = Conv
Pad -> MaxPool = MaxPool
Major Conditions:
- It will only fuse for the `Constant` mode of padding.
- Conv/MaxPool should not have optional `indices` output tensor
- Padding value for non-spatial dimensions should be zero and for
spatial dimensions padding values should be positive for `pad` operator.
For other conditions please see `SatisfyCondition()` in `pad_fusion.cc`.
### Motivation and Context
<!-- - Why is this change required? What problem does it solve?
- If it fixes an open issue, please link to the issue here. -->
