UConvert tests for signed int operand type

UConvert tests for signed int operand type

OpUConvert where the operand type is a signed integer type.

Add tests:
 * dEQP-VK.spirv_assembly.instruction.compute.uconvert.int*
 * dEQP-VK.spirv_assembly.instruction.graphics.uconvert.int*

Affects:
 * dEQP-VK.spirv_assembly.instruction.compute.uconvert.*
 * dEQP-VK.spirv_assembly.instruction.compute.uconvert.*

Components: Vulkan

VK-GL-CTS issue: 1876

Change-Id: I0cee4fa43fab995ef20dcc30454d910ce371bb6e
(cherry picked from commit b0eda2776125d76c3ef3df394d6c224271f90f95)