Adding teams support for Archer:
- data management in initial-task-begin/end is different for the initial tasks in a league than for the initial task representing the OpenMP program.
- storing the flag from the parallel begin allows to distinguish league and parallel team
- according to OpenMP implicit flush semantics, the end of initial tasks in a league is before the program can continue execution at the end of the teams region.
- in contrast, for a parallel region, the synchronization happens in the implicit barrier and the parallel-end event should not be involved.