BufferedFileTest.Fileno sometimes take a very long time.

[edge90]

15: [WARNING] fmt-7.1.3/test/gmock-gtest-all.cc:7179:: Death tests use fork(), which is unsafe particularly in a threaded context. For this test, Google Test couldn't detect the number of threads.
15: [       OK ] BufferedFileTest.Fileno (300168 ms)
15: [----------] 12 tests from BufferedFileTest (300168 ms total)

Linux hostname 4.18.0-193.14.3.el8_2.x86_64 #1 SMP Mon Jul 20 15:02:29 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
gcc 10

[vitaut]

This test is quite problematic because some implementations don't check if the file pointer is null. I removed it since it's covered by posix-mock-tests anyway. Thanks for reporting.