Share instance/device across test case instances in dEQP-VK.synchronization.*

Share instance/device across test case instances in dEQP-VK.synchronization.*

Some of the dEQP-VK.synchronization.* test groups create new devices or new
instances for each test case. This is a really expensive thing to do tens of
thousands of times, and makes this the longest-running test group in the CTS.
This change uses singleton objects to store the instance/device, and adds
cleanup callbacks to destroy the singletons when the group is finished.

VK-GL-CTS Issue: 1886
Components: Vulkan
Affects: dEQP-VK.synchronization.*

Change-Id: If935b457276790faf4a86e6f2afb5fd911987a85
(cherry picked from commit 90e05499c49c88fc4063748574931c3be5652b07)