While moving device_plugin_handler_test.go from pkg/kubelet/cm/ to
pkg/kubelet/cm/deviceplugin/, we can no longer uses cm in its tests
because that would cause a cycle dependency. To solve this problem,
I moved the main cm GetResources functionality as well as part of the
current device plugin handler Allocate functionality into a new device
plugin handler function, GetDeviceRunContainerOptions(). This
refactoring is also needed by another PR 51895 that moves device
allocation into admission phase. Now device plugin handler Allocate()
first checks whether there is cached device runtime state and only
issues Allocate grpc call if there is no cached state available.
The new GetDeviceRunContainerOptions() function simply returns device
runtime config from the cached state. To support this change, extended the
podDevices struct and checkpoint data structure with device runtime state.