Use ceilMode from pytorch MaxPool in shlo to get correct output shape

[brataTT]

Pytorch passes an argument ceilMode into MaxPool op.
Currently, torch to stablehlo conversion does not use it to determine stablehlo output shape.

This change intends to use the same logic as torch to use ceilMode when calculating output shape.
During conversion, we make up the size difference using padding.

Changes:

• Use ceilMode param the way torch uses it.
• Added tests for both floor and ceil cases.

[brataTT]

@qingyunqu
from recent changes, I think you'd be the person to ask for reviews
lmk if anyone else would be more appropriate

[penguin-wwy]

@brataTT
Due to upstream issues with stablehlo #4152 (comment), the CI tests for stablehlo are currently disabled. Unless there are special circumstances, we hope that PRs related to stablehlo can wait until the CI is re-enabled before being merged.

[brataTT]

@penguin-wwy
Thank you for the info.
No special circumstances here.
And definitely want to verify the change before merging.

Please let me know if you spot any improvements I can make to the change while we wait for CI to be re-enabled.