Dial EventBase loop time logging up to 11
Dial EventBase loop time logging up to 11

Summary:
There is no need for EventBase to log every loop iteration on a relatively low VLOG level.
Just move it up to 11 like the other verbose logging in EventBase.cpp

Reviewed By: yfeldblum

Differential Revision: D4642379

fbshipit-source-id: 351636afb186ba94b2447b206d7d1389cbdba110

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