- according spec 1.4, annex C shmem collectives should process
calls where number of elements is zero independently from pointer
value
- added zero-count processing - it just call barrier to
sync ranks
Signed-off-by: Sergey Oblomov <sergeyo@mellanox.com>
(cherry picked from commit 9de128afaf5224193a88f00c897f5d5c94336f99)