This patch remove the Operation *op from the argument list in utility functions, and directly pass the Location instead of calling op->getLoc().
This should make the code more clear, as the utility function (logically) does not relies on the operation that we are currently rewriting, and they behave the same regardless of the operation.
This is of course less precise then the op's loc, but I am not sure how much effort we really put in keeping locations very up to date