swapchain: add intercept_khr_swapchain_command
swapchain: add intercept_khr_swapchain_command

It returns the function pointers for all intercepted VK_KHR_swapchain
commands.  Call intercept_khr_swapchain_command from GetDeviceProcAddr.

KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools