stablehlo while with non-affine bound

we can just create a new induction variable which tracks the current iteration, and use that at the end of the loop to determine how much to allocate

cc @Pangoraw

No file, test, or entry point is named. Start by locating the StableHLO while handling for non-affine bounds and trace how allocation size is determined. Done means the loop tracks its current iteration and uses that value to determine the allocation size.

Written by the indexing model from the issue text.