This should prevent from cache stats counters going down after cache rotation,
which may corrupt `cache hit ratio` graph on the official Grafan dasbhoards
when using the following query:
1 - (sum(rate(vm_cache_misses_total[5m])) by (type) / sum(rate(vm_cache_requests_total[5m])) by (type))
This should reduce the amount of RAM required for processing time series
with non-zero churn rate.
The previous cache behavior can be restored with `-cache.oldBehavior` command-line flag.