Fix unintentional skipping of tests

Fix unintentional skipping of tests

cd11d001fe86 ("Support skipping tests from test{,_device}()") breaks a
good handful of tests.

For example, block/005 uses _test_dev_is_rotational to check if the
device is rotational and uses the result to size up the fio run. As a
side-effect, _test_dev_is_rotational also sets SKIP_REASON, which (since
commit cd11d001fe86) causes the test to print out a "[not run]" even
through the test actually ran successfully.

Fix this by renaming the existing helpers to _require_foo (e.g. a
_require_test_dev_is_rotational) and add the non-_require variant where
needed.

Fixes: cd11d001fe86 ("Support skipping tests from test{,_device}()")
Reviewed-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
[Omar: simplify new _test_dev helpers]
Signed-off-by: Omar Sandoval <osandov@fb.com>