Vulkan DCE: Track the use of immutable samplers (#1831)
Vulkan DCE: Track the use of immutable samplers (#1831)

The read of immutable samplers should be tracked at
vkCreateDescriptorSetLayout, so that later use of a descriptor allocated
based on the descriptor set layout will keep the samplers alive.

It is more correct to have the samplers filling in the descriptor slots
in the corresponding binding/array elements of the descriptor sets
allocated based on the layout. But this is not necessary, as the
dependency has already be tracked by the chain of desscriptor set ->
descriptor layout -> immmutable samplers.
Qining/gapid,google/gapid,pmuetschard/gapid,Qining/gapid,google/gapid,Qining/gapid,google/gapid,Qining/gapid,google/agi,pmuetschard/gapid,Qining/gapid,pmuetschard/gapid,google/gapid,google/gapid,google/gapid,google/agi,Qining/gapid,pmuetschard/gapid,google/gapid,google/agi,pmuetschard/gapid,Qining/gapid,google/agi,pmuetschard/gapid,pmuetschard/gapid,pmuetschard/gapid,Qining/gapid,google/agi,google/agi,google/agi,google/agi,google/gapid