Some code in preparation to implement double stack (SECOND_VECTOR_DOUBLE_STACK).
Some code in preparation to implement double stack (SECOND_VECTOR_DOUBLE_STACK).

GPUOpen-LibrariesAndSDKs/VulkanMemoryAllocator,GPUOpen-LibrariesAndSDKs/VulkanMemoryAllocator,GPUOpen-LibrariesAndSDKs/VulkanMemoryAllocator