CRI runtimes do not supply cpu nano core usage as it is not part of CRI
stats. However, there are upstream components that still rely on such
stats to function. The previous fix was faulty because the multiple
callers could compete and update the stats, causing
inconsistent/incoherent metrics. This change, instead, creates a
separate call for updating the usage, and rely on eviction manager,
which runs periodically, to trigger the updates. The caveat is that if
eviction manager is completley turned off, no one would compute the
usage.
