Reduce NumSingleJitRequests to 0

Summary: The cpu spike at warmup still looks bad at 5

Reviewed By: @bertmaher

Differential Revision: D1562206
revert folly using that file

Summary:
I'd rather a folly fix anyways. This bandaid is horrible.

@fredemmott this will be needed for 3.3

Test Plan: cmake contbuild

Reviewers: sgolemon, fredemmott, paulbiss, joelm

Reviewed By: joelm

Subscribers: trunkagent, hphp-diffs@, ps, fredemmott

Differential Revision: https://phabricator.fb.com/D1562855