Add test for concurrent compute

Add test for concurrent compute

Added test that runs identical payload on two queues with different
priority levels, and checking that the lower priority queue does not
finish first, adding a note to the log if the priorities seem to be
reversed. At the end it is also verified that both queues did the
work.

New test:

dEQP-VK.compute.basic.concurrent_compute

Components: Vulkan

VK-GL-CTS issue: 1509

Change-Id: Ib5d52dcbb3cee0e07c4d14bbb8d61d2f1ee2a8c5