Extract common functions in shift and rotate to another file

[onurinanc]

let P_B: col = b;
let P_ROW: col = row;
let P_operation: col = op;
let c: int -> int = |i| match op(i)

As in the example above, some parts are common to both shift and rotate machine which needs to be extracted into a common file.

This is the related comment #1884 (comment)