Emit defined positions from tessellation shader in subgroups tests.

Emit defined positions from tessellation shader in subgroups tests.

Use only defined components of gl_in[] in tessellation evaluation shader:
the tessellation control shader emits only one vertex in patch, so the value
of gl_in[1] is undefined. The code is changed to use only gl_in[0].

Additionally fix geometry shader input primitive topology, when tessellation
shaders are used: tessellation outputs isolines, so geometry input should
be lines, not points.

Affects: dEQP-VK.subgroups.*graphic

Components: Vulkan

VK-GL-CTS issue:  924

Change-Id: Id1984a387a32c50e0f86638bf3d6b0273a7633d8