Allocate private/local buffers for slices accurately during fusion

- the size of the private memref created for the slice should be based on
  the memref region accessed at the depth at which the slice is being
  materialized, i.e., symbolic in the outer IVs up until that depth, as opposed
  to the region accessed based on the entire domain.

- leads to a significant contraction of the temporary / intermediate memref
  whenever the memref isn't reduced to a single scalar (through store fwd'ing).

Other changes

- update to promoteIfSingleIteration - avoid introducing unnecessary identity
  map affine_apply from IV; makes it much easier to write and read test cases
  and pass output for all passes that use promoteIfSingleIteration; loop-fusion
  test cases become much simpler

- fix replaceAllMemrefUsesWith bug that was exposed by the above update -
  'domInstFilter' could be one of the ops erased due to a memref replacement in
  it.

- fix getConstantBoundOnDimSize bug: a division by the coefficient of the identifier was
  missing (the latter need not always be 1); add lbFloorDivisors output argument

- rename getBoundingConstantSizeAndShape -> getConstantBoundingSizeAndShape

PiperOrigin-RevId: 230405218