demos: Fix argument consistency for smoketest
demos: Fix argument consistency for smoketest

All arguments now have double-dashes

Change-Id: I19548d60a008cc259326efb1b62b6fd9d3bbdd70

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