[mlir][openacc] Add legalize data pass for compute operation (#80351)

This patch adds a simple pass to replace the uses inside compute
operation. It replaces the `varPtr` values with their corresponding
`accPtr` values gathered through the dataClauseOperands.

private and reductions variables are not included in this pass since
they will normally be replace when they are materialized.

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Co-authored-by: Slava Zakharin <szakharin@nvidia.com>