Tests for global atomic operations

Tests for global atomic operations

This commits adds new tests to check atomic operations work as expected
when used with global shared memory variables in compute shaders
(Workgroup storage in SPIR-V).

In addition, this commit fixes a missing barrier to make writes
available to the host domain before invalidating memory.

New tests:
dEQP-VK.glsl.atomic_operations.*_shared

Affected tests:
dEQP-VK.glsl.atomic_operations.*

Components: Vulkan
VK-GL-CTS issue: 2400

Change-Id: Id5e59c9acb1acbee284f98813091d4a6f31ee169