Added tests for different shader varying vec width

Added tests for different shader varying vec width

Vulkan specification (1.0.8, 14.1.3) states that vertex and fragment
shader varyings may differ as long as they are of the same type and the
vertex shader outputs at least as wide vectors as the fragment shader
inputs.

This set of tests link various varying vector types, all of which
are legal even though they do not match.

Affects:

dEQP-VK.glsl.linkage.varying.rules.legal_mismatch_vec4_vec3
dEQP-VK.glsl.linkage.varying.rules.legal_mismatch_vec4_vec2
dEQP-VK.glsl.linkage.varying.rules.legal_mismatch_vec4_float
dEQP-VK.glsl.linkage.varying.rules.legal_mismatch_vec3_vec2
dEQP-VK.glsl.linkage.varying.rules.legal_mismatch_vec3_float
dEQP-VK.glsl.linkage.varying.rules.legal_mismatch_vec2_float
dEQP-VK.glsl.linkage.varying.rules.legal_mismatch_ivec4_ivec3
dEQP-VK.glsl.linkage.varying.rules.legal_mismatch_ivec4_ivec2
dEQP-VK.glsl.linkage.varying.rules.legal_mismatch_ivec4_int
dEQP-VK.glsl.linkage.varying.rules.legal_mismatch_ivec3_ivec2
dEQP-VK.glsl.linkage.varying.rules.legal_mismatch_ivec3_int
dEQP-VK.glsl.linkage.varying.rules.legal_mismatch_ivec2_int

Components: Vulkan

VK-Gl-CTS issue: 821

Change-Id: I4afc3edb77fd6f421cafce20d09bbdd948f16dcf