[prefetch]: Add support for prefetching load operations using a tensor of pointers (#4064)

Loads with tensor of pointers operands that have been proven to
reference memory in row major (and are contained in a scf.for loop)
order are now prefetched using 2D prefetching intrinsics.

Note: This PR is derived from PR #3634

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Signed-off-by: Tiotto, Ettore <[email protected]>

Author: etiotto