Once the number of buffers or images exceeds the QVarLengthArray limit,
it moves over to heap-based allocation, and then reallocated to grow as
needed. Problem is, if we keep references to the elements, those may get
invalidated on every grow. This was not an issue until the element count
reached the preallocated (stack) count.
So instead, store indices and fill in the pointers in the VkWriteDescriptorSet
only before issuing vkUpdateDescriptorSets().
Change-Id: I99f26f5e14cb28107edb1db86a21afa135858589
Reviewed-by: Paul Olav Tvete <paul.tvete@qt.io>
71e9c2f036