kselftest: membarrier: convert to TAP13 output

Make the membarrier test output in the TAP13 format by using the
TAP13 output functions defined in kselftest.h

Signed-off-by: Paul Elder <paul.elder@pitt.edu>
Signed-off-by: Alice Ferrazzi <alice.ferrazzi@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>