[mlir] Avoid folding `index.remu` and `index.rems` for 0 rhs

As discussed in https://github.com/llvm/llvm-project/issues/59714#issuecomment-1369518768, the folder for the remainder operations should be resillient when the rhs is 0.
The file `IndexOps.cpp` was already checking for multiple divisions by zero, so I tried to stick to the code style from those checks.

Fixes #59714.

As a side note, is it correct that remainder operations are never optimized away? I would expect that the following code

```
func.func @remu_test() -> index {
  %c3 = index.constant 2
  %c0 = index.constant 1
  %0 = index.remu %c3, %c0
  return %0 : index
}
```
would be optimized to
```
func.func @remu_test() -> index {
  return index.constant 0 : index
}
```
when called with `mlir-opt --convert-scf-to-openmp temp.mlir`, but maybe I'm misunderstanding something.

Reviewed By: Mogball

Differential Revision: https://reviews.llvm.org/D151476