inefficient "ordered" scheduling 

An ordered loop is not optimized well, which causes sometimes a timeout in `test/worksharing/for/omp_for_collapse.c` if execution streams are oversubscribed.
```c
  #pragma parallel omp for ordered
  for (i = 1; i < 10000; i++) {
    #pragma omp ordered
    comp(i);
  }
```
Although `order` is not widely used, it should be optimized by using synchronization primitives.