Add tests for OpSwitch operator

Add tests for OpSwitch operator

This create tests for SPIR-V OpSwitch with different integer types.

It provides tests using 32-bit and 64-bit signed and unsigned integers.
But it is designed to easily extend to other types, like 16-bit
integers.

New tests:
dEQP-VK.spirv_assembly.type.scalar.*.switch_*

VK-GL-CTS issue: 995

Components: Vulkan

Change-Id: I4940f5853c81dff0191c3d352ddbf439eb0ea560