MFC r282067:

Integrate tools/regression/fifo into the FreeBSD test suite as tests/sys/fifo
and tools/regression/file into the FreeBSD test suite as tests/sys/file

Integrate tools/regression/fifo into the FreeBSD test suite as tests/sys/fifo
and tools/regression/file into the FreeBSD test suite as tests/sys/file

MFC after: 1 week

Integrate tools/regression/file into the FreeBSD test suite as tests/sys/file

Integrate more tests into the FreeBSD test suite from tools/regression, etc

Fix fcntl F_GETFL F_SETFL for files opened execute-only (O_EXEC).

The FFLAGS and OFLAGS now work correctly also for files opened with O_EXEC.
Except possibly fuse, the other users pass values without O_EXEC set. fuse
appears to assume O_EXEC is handled correctly.

Although F_SETFL may not be commonly used for execute-only file descriptors,
F_GETFL may be useful to find the access mode.