Add depthBounds tests for VK_EXT_depth_range_unrestricted

Add depthBounds tests for VK_EXT_depth_range_unrestricted

Added tests check that depthbounds range values outside [0.0f, 1.0f]
are properly supported by the drivers.

This test will draw the same scene two times. The first time, it will
render the points depending on if they pass the depth test and if clear
depth value passes the depthBounds test.

The second time, will render the same scene but the the point positions
will have depth buffer values from the first draw. If they pass the
depth test, then the depthBounds test will check the previous content
of the depth buffer, which is most cases, will make that the second
image differs from the first one.

Added new tests:

    dEQP-VK.pipeline.depth_range_unrestricted.depthbounds.*

Components: Vulkan
VK-GL-CTS issue: 1754

Change-Id: Ica136efd9e946db63b2092914566d43214b7b641