[Flang][MLIR] Move setOpenMPIntegerWrapAround function into the OpenMP dialect (#217448)
- Fixed the linker error: `undefined reference
to'mlir::omp::IntegerWrapAroundAttr::get(mlir::MLIRContext*, bool)'`
mentioned in mentioned in
[PR#214165](https://github.com/llvm/llvm-project/pull/214165#issuecomment-5323821248)
by moving the `setOpenMPIntegerWrapAround(...)` helper function out of
`flang/Tools/CrossToolHelpers.h` and placed it into the OpenMP dialect
utilities.