tests:Fix DynViewportAndScissorMismatch crash
tests:Fix DynViewportAndScissorMismatch crash

This test was crashing on Nvidia drivers.
The crash seems to be a driver bug as the workaround is to not destroy
a descriptor set layout prior to creating gfx pipelines whose
pipeline_layout object was created from the given descriptor set layout

KhronosGroup/Vulkan-LoaderAndValidationLayers,KhronosGroup/Vulkan-LoaderAndValidationLayers,KhronosGroup/Vulkan-LoaderAndValidationLayers,KhronosGroup/Vulkan-LoaderAndValidationLayers