layers: Add binding between buffer and cmd buffer
layers: Add binding between buffer and cmd buffer

Updated call mechanism to create binding between a VkBuffer
and a VkCommandBuffer so that it occurs in a single call.
Removed old mem_tracker mechanism for looking up memory from
a buffer and just use mem in BUFFER_NODE instead.
Also simplified call to check valid buffer use flags in order
to avoid a redundant map look-up.

Will make similar changes for images next.

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