Fragment input components limit includes position

Fragment input components limit includes position

The Vulkan limits maxFragmentInputComponent is inclusive of any
components that are being used up by the built-in interface block.

This means that the test of n components should consist of 4 components
for the position and (n - 4) user defined components.

The test should also check the maxVertexOutputComponent limit as
technically there is no implied >= requirement.

Affects:

dEQP-VK.glsl.limits.near_max.fragment_input.components_*

Component: Vulkan

VK-GL-CTS Issue: 1597

Change-Id: I58adbbbaaa94dd185b024f63519dac7daf5e4b3c