refactor: delete unused unit test (#1354)
refactor: delete unused unit test (#1354)

Summary:
There are some duplicated unit test in TokenBucketTest.cpp. So this pr is intent to delete these unused unit test.
Pull Request resolved: https://github.com/facebook/folly/pull/1354

Reviewed By: yfeldblum

Differential Revision: D21061401

Pulled By: Orvid

fbshipit-source-id: ea486fc244e2be68196ef015e020b8664bb3670a

facebook/folly,facebook/folly,facebook/folly,facebook/folly,facebook/folly