- Cases with a NULL global_work_size were not tested
- The specification states that zero-sized enqueues behave similarly to
marker commands. Test that events for NDRange kernel commands have the
correct CL_COMMAND_NDRANGE_KERNEL command type to guard against
implementations naively using a marker command.
- Tidy up the code a bit and add missing error checking.
Signed-off-by: Kévin Petit <kpet@free.fr>