re PR libgomp/49490 (suboptimal load balancing in loops)

	PR libgomp/49490
	* omp-low.c (expand_omp_for_static_nochunk): Only
	use n ceil/ nthreads size for the first
	n % nthreads threads in the team instead of
	all threads except for the last few ones which
	get less work or none at all.

	* iter.c (gomp_iter_static_next): For chunk size 0
	only use n ceil/ nthreads size for the first
	n % nthreads threads in the team instead of
	all threads except for the last few ones which
	get less work or none at all.
	* iter_ull.c (gomp_iter_ull_static_next): Likewise.
	* env.c (parse_schedule): If OMP_SCHEDULE doesn't have
	chunk argument, set run_sched_modifier to 0 for static
	resp. 1 for other kinds.  If chunk argument is 0
	and not static, set value to 1.

From-SVN: r175315