scripts:Allow duplicate exceptions for some ids
scripts:Allow duplicate exceptions for some ids

Added global duplicate_exceptions list at the top of the script that
is used to store any IDs that are allowed to be used multiple times
in the source. An explanation comment of all exceptions should be
included.

Initial exception included in list is VALIDATION_ERROR_00942 which is
a descriptor set update error to make sure a valid sampler is included
for relevant write updates. This is re-used for two copy updates that
may have invalid samplers.

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