[reporting] refactor StatsLogs into its own module in InferPrint
[reporting] refactor StatsLogs into its own module in InferPrint

Summary:
- StatsLogs is now its own functional module in InferPrint
	- No longer stores events to be logged in a list to be later logged, just immediately logs them

Reviewed By: dulmarod

Differential Revision: D7010559

fbshipit-source-id: 1837ca9

facebook/infer,facebook/infer,facebook/infer,jvillard/infer,jvillard/infer,jvillard/infer,jvillard/infer,facebook/infer,facebook/infer,jvillard/infer,jvillard/infer,facebook/infer,facebook/infer,jvillard/infer