Add AMD FMASK and EQAA extension tests

Add AMD FMASK and EQAA extension tests

Adds tests for:
- VK_AMD_shader_fragment_mask
- VK_AMD_mixed_attachment_samples

VK_AMD_shader_fragment_mask extension provides efficient read access to the
fragment mask in compressed multisampled color surfaces. The fragment mask is
a lookup table that associates color samples with color fragment values.

VK_AMD_mixed_attachment_samples extension enables applications to use
multisampled rendering with a depth/stencil sample count that is larger than
the color sample count. Having a depth/stencil sample count larger than
the color sample count allows maintaining geometry and coverage information
at a higher sample rate than color information.

Components: Vulkan
VK-GL-CTS issue: 2104

Affected tests:
dEQP-VK.pipeline.multisample.sample_locations_ext.*

New tests:
dEQP-VK.pipeline.multisample.mixed_attachment_samples.*
dEQP-VK.pipeline.multisample.shader_fragment_mask.*

Change-Id: If4876eda00dcd2bac4f685252048c5afd58d3df5