Summary:
The original `EnvPosixTest.RunImmediately` assumes that after scheduling
a background thread, the thread is guaranteed to complete after 0.1 second.
I do not know about any non-real-time OS/runtime providing this guarantee. Nor
does C++11 standard say anything about this in the documentation of `std::thread`.
In fact, we have observed this test failure multiple times on appveyor, and we
haven't been able to reproduce the failure deterministically. Therefore,
I disable this test for now until we know for sure how it used to fail.
Instead, I add another test `EnvPosixTest.RunEventually` that checks that
a thread will be scheduled eventually.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4126
Differential Revision: D8827086
Pulled By: riversand963
fbshipit-source-id: abc5cb655f90d50b791493da5eeb3716885dfe93
520bbb1774