58660bf21a
Summary: `histogram_test` uses real sleep, which depends on the test executing speed, it makes the test unstable. Switching to using a mock time env, it can also increase the test speed (from 10100ms -> 100ms). Pull Request resolved: https://github.com/facebook/rocksdb/pull/7799 Test Plan: run test 10 times, all passed. vs. without fix 3 out 10 test failed: no fix: https://app.circleci.com/pipelines/github/facebook/rocksdb?branch=pull%2F7797 with fix: https://app.circleci.com/pipelines/github/facebook/rocksdb?branch=pull%2F7799 Reviewed By: pdillinger Differential Revision: D25676948 Pulled By: jay-zhuang fbshipit-source-id: 64c273fc299c53283138dbb213386e4b45e8bdc2