scripts: Remove enum/struct_validate_helper funcs
scripts: Remove enum/struct_validate_helper funcs

From vk_helper.py.  These were not used in the codebase.

Change-Id: I3cc80e34eb831122ce8c54dbc004a003e02a47fe

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