layers:Verify valid buffer for tex buff ds update
layers:Verify valid buffer for tex buff ds update

Fixes #2104

Make sure that buffer underlying the bufferView of texel buffer for a
uniform or storage texel buffer update has a valid buffer behind it.
Object tracker only checks to make sure that the view itself hasn't
been destroyed, so need this extra level of checking at this level to
avoid crash.

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