test: remove tst.alignring.d

This test produces excessive output, writing 100Ks of lines to runtest.log.
It tests nothing, in that the output is not checked.  Also, it targets ring
buffering, which means something entirely different in the current
implementation than it did in Solaris.

Remove the test.

Signed-off-by: Eugene Loh <eugene.loh@oracle.com>
Reviewed-by: Kris Van Hees <kris.van.hees@oracle.com>