[misc] Add print and fix bug during shutdown where CoreManager was used by the log after destruction.
[misc] Add print and fix bug during shutdown where CoreManager was used by the log after destruction.

mit-carbon/Graphite-Cycle-Level,8l/Graphite,mit-carbon/Graphite-Cycle-Level,mit-carbon/Graphite,victorisildur/Graphite,fhijaz/Graphite,nkawahara/Graphite,mit-carbon/Graphite,nkawahara/Graphite,nkawahara/Graphite,mit-carbon/Graphite-Cycle-Level,8l/Graphite,fhijaz/Graphite,nkawahara/Graphite,mit-carbon/Graphite,8l/Graphite,8l/Graphite,mit-carbon/Graphite,victorisildur/Graphite,victorisildur/Graphite,fhijaz/Graphite,fhijaz/Graphite,victorisildur/Graphite,mit-carbon/Graphite-Cycle-Level