Disable calls to fcntl.fcntl(…, fcntl.F_SETFD, … | fcntl.FD_CLOEXEC) with Python >=3.4,
since FD_CLOEXEC is enabled by default in Python >=3.4.
SpawnProcess: Don't handle FreeBSD fcntl ENOTTY

This error does not occur since the fcntl call was fixed to properly
use the F_GETFD/F_SETFD commands in commit
30c652a9db1014fc720f7d6055520a07b731c984.
PipeReaderTestCase: use PopenProcess