layers: Shadow descriptor set layout in ShaderChecker
layers: Shadow descriptor set layout in ShaderChecker

Signed-off-by: Chris Forbes <5dcac483e7a6e31a5cbe89f38cc69dff8ee93dac@ijw.co.nz>
Reviewed-by: Courtney Goeltzenleuchter <de5e92d0aa220e70735ac740f87439cfa8f82eb2@lunarg.com>

KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools