MFC r293821:

Integrate
tools/regression/geom_{concat,eli,gate,mirror,nop,raid3,shsec,stripe,uzip}
in to the FreeBSD test suite as
tests/sys/geom/class/{concat,eli,gate,mirror,nop,raid3,shsec,stripe,uzip}

The tools/regression/geom and tools/regression/geom_part testcases are being
left alone because both test sets are both currently broken.

The majority of this work was done on ^/user/ngie/more-tests2 . The differences
are as follows:
- tests/sys/geom/class/Makefile.inc is not present; it was
inlined into the class's Makefiles for explicitness.
- The testcases officially require root via kyua
- The geom_gate(4) tests don't use the pidfile changes proposed in
https://reviews.freebsd.org/D4836 .

Integrate
tools/regression/geom_{concat,eli,gate,mirror,nop,raid3,shsec,stripe,uzip}
in to the FreeBSD test suite as
tests/sys/geom/class/{concat,eli,gate,mirror,nop,raid3,shsec,stripe,uzip}

The tools/regression/geom and tools/regression/geom_part testcases are being
left alone because both test sets are both currently broken.

The majority of this work was done on ^/user/ngie/more-tests2 . The differences
are as follows:
- tests/sys/geom/class/Makefile.inc is not present; it was
inlined into the class's Makefiles for explicitness.
- The testcases officially require root via kyua
- The geom_gate(4) tests don't use the pidfile changes proposed in
https://reviews.freebsd.org/D4836 .

MFC after: 1 month
Sponsored by: EMC / Isilon Storage Division

- Add a geom_raid3 specific cleanup function and trap on that function at
exit so things are cleaned up properly
- Use attach_md for attaching md(4) devices
- Don't hardcode /tmp for temporary files, which violates the kyua sandbox

MFC after: 3 weeks
Sponsored by: EMC / Isilon Storage Division

Use randomly generated device names in testcases via mktemp -u instead of using
the hardcoded device name, "test"

MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division

Convert graid3(8) regression tests to the new framework.

Fix incorrect comment.

MFC after: 3 days

When RAID3 device is configured in "verify" mode, synchronization of the
parity component is now force on creation.
Change regression test which check "verify" mode to work properly after
this change.

Regression tests for 'verify reading' algorithm.

Add regression test for the new "round-robin reading" feature.

Add regression tests for GEOM_RAID3.