VK_EXT_image_robustness tests

VK_EXT_image_robustness tests

Re-uses much of the robustness2 test code.
Parameterizes the code to test just the subset
of robustness2 relevant to image_robustness
with the appropriate relaxations.

New tests: dEQP-VK.robustness.image_robustness.*

Affects: dEQP-VK.robustness.robustness2.*

Components: Vulkan

Change-Id: Ifaf4ffe4e4718cc7e80afc305ab73e8c9ea1ff4a