Allow geometry shader to reorder vertices in dEQP-VK.ray_query.acceleration_structure...

Allow geometry shader to reorder vertices in dEQP-VK.ray_query.acceleration_structures test

This fixes the geometry shader used in the test to allow gl_in[] to start from
arbitrary vertex from the triangle primitive.

According to spec:

"""
24.1. Geometry Shader Input Primitives
...
Vertices may be in a different absolute order to that specified by the topology,
but must adhere to the specified winding order.
"""

The test does some ray query computation in geometry shader, using elements
of gl_in[] as inputs, and storing the outputs in consecutive pixels of storage image.
The test than verifies the image contents using some predefined vertex order.
As gl_in is not queranteed to follow this order, vertex index from vertex shader is now
used to calculate starting index, from which gl_in is iterated.

Components: Vulkan

VK-GL-CTS Issue: 2764

Change-Id: I1b6b8df3166d40132747a7315366c427e32b0007
Affects: dEQP-VK.ray_query.acceleration_structures.*.geometry_shader.*