layers:Remove redundant checks
layers:Remove redundant checks

Remove descriptor set check to make sure that src & dest descriptor
sets of copy update are valid. Object_tracker already verifies this.

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