Add tests for VK_EXT_shader_atomic_float2

Add tests for VK_EXT_shader_atomic_float2

New tests:
dEQP-VK.glsl.atomic_operations.*float16*
dEQP-VK.glsl.atomic_operations.min_float*
dEQP-VK.glsl.atomic_operations.max_float*
dEQP-VK.image.atomic_operations.min*r32f*
dEQP-VK.image.atomic_operations.max*r32f*

Affects:

dEQP-VK.glsl.atomic_operations.*float*
dEQP-VK.image.atomic_operations.add*r32f*
dEQP-VK.image.atomic_operations.exchange*r32f*

Components: Vulkan

VK-GL-CTS issue: 2566

Change-Id: I7462cc74e799c2245407220fa9db7e5b659f86f4
(cherry picked from commit ca4e5aff66bccbbe88935c10e2c55a3147c1fc03)