Remove $FreeBSD$: two-line .h pattern

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/

Tweak r319058 slightly

- Specify an explicit mode when using O_CREAT per open(2).
- Fix the error message (add missing enclosing parentheses).

Submitted by: jilles
MFC after: 3 days
MFC with: r319058
Sponsored by: Dell EMC Isilon

Create a deterministic file in the kyua sandbox, instead of a
temporary file outside the kyua sandbox

This helps ensure that the file is removed at test exit, and as
a side effect, cures a warning about umasks with Coverity.

MFC after: 3 days
Sponsored by: Dell EMC Isilon

tests/sys/file/ftruncate_test: use an exit code of 1 instead
of -1 with err*(3).

An exit code of -1 is implementation defined -- it's best to stick
with something well-defined (1).

MFC after: 3 days
Sponsored by: Dell EMC Isilon

Remove unused vars to fix -Wunused issues

MFC after: 3 days
Sponsored by: Dell EMC Isilon

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