Delete unused stat counters
Summary: All of these are unused. I suspect some of them were originally meant to
count something that we still care about (e.g. tracelet guard
executions?) but the callsites have bitrotted away.
I think we'll need automated testing if we care about a particular stat
enough to keep it. I'd like to check this diff in as-is, but it's also
partially a forcing function to get people to reinstate stat counters
that they actually care about.
Reviewed By: @edwinsmith
Differential Revision:
D1515024